17 Most Common Tax Mistakes Made During Divorce (w/Examples) + FAQs

The single biggest tax mistake in a divorce is focusing on an asset’s market value (what it’s worth today) instead of its after-tax value (what you actually get to keep).

The primary conflict stems from a federal law: Internal Revenue Code (IRC) § 1041. This rule states that transferring property between spouses “incident to divorce” is not a taxable event. While this sounds good, it has a hidden trap called “carryover basis.” This rule requires the person receiving the asset to also inherit the original tax bill, which could be decades old.

The consequence is a financial disaster. One spouse may receive an asset that is a “tax time-bomb,” while the other walks away with an asset of the same value tax-free. In one common scenario, this mistake can create an instant, unexpected tax liability of over $166,000.

Here is what you will learn to avoid that and other costly errors:

🏠 How to navigate the $250,000 vs. $500,000 home sale exclusion and avoid a massive capital gains tax bill.
📜 Why your divorce decree alone is worthless for splitting 401(k)s and pensions, and what the QDRO document really is.
👶 The specific IRS form (Form 8332) that legally determines who claims the children—and why it overrides your court order.
🚫 How the Tax Cuts and Jobs Act (TCJA) completely changed the rules for alimony, making old advice financially dangerous.
🛡️ How to protect yourself from your ex-spouse’s tax fraud, even after you signed a joint return, using “Innocent Spouse Relief.”

Part 1: The First-Year Filing Traps

These initial mistakes happen during the first tax season after you separate. They set a dangerous financial pattern and are often the easiest to avoid.

Mistake 1: Choosing the Wrong Tax Filing Status

The most common point of confusion is what status to file for the year you separate. The Internal Revenue Service (IRS) does not care about your separation date. It follows one, simple, binding rule: your marital status on December 31st determines your filing options for the entire tax year.

If your divorce decree is final on or before December 31, the IRS considers you “unmarried” for the whole year. You must file as Single or, if you qualify, Head of Household.

If your divorce is not final by December 31 (even if it’s final on January 1), you are considered “married” for the entire previous tax year. Your only options are Married Filing Jointly (MFJ) or Married Filing Separately (MFS). Many people incorrectly file “Single” because they live apart, which is a direct violation of tax law and can trigger an audit.

This “December 31st Rule” is a powerful strategic tool. If you are in mediation in December, you have a major financial choice. You can rush to finalize the divorce by December 31 to unlock the “Single” or “Head of Household” status. Or, you can intentionally delay signing until January 1 to preserve the “Married Filing Jointly” status one last time, which often provides the lowest tax for both parties.

Mistake 2: Forfeiting the “Head of Household” Status

Do not file as “Single” if you can file as “Head of Household” (HoH). The HoH status is significantly better, giving you a larger standard deduction and more favorable tax brackets.

To qualify, you must be “unmarried” (or “considered unmarried” by the IRS) on December 31, pay for more than half the cost of keeping up your home, and have a “qualifying person” (like your child) live with you for more than half the year.

Here is the critical trap: Many parents believe whoever “claims the child” as a dependent also gets to file as HoH. This is false. The right to claim a child as a dependent can be traded (see Mistake 12). The right to file as Head of Household cannot be traded. It always belongs to the custodial parent, who is the parent the child lived with for the most nights during the year.

Mistake 3: Failing to Update Your Form W-4 at Work

When you were married, your employer withheld taxes from your paycheck based on your “Married” status. This status withholds money at a much lower rate. Once you are divorced, you are required by law to give your employer a new Form W-4 within 10 days to change your status to “Single.”

This is a human-factors failure. You are dealing with the emotional and logistical chaos of a divorce and updating an HR form is the last thing on your mind.

The consequence is a massive, “surprise tax bill” at the end of your first year of being single. Because your employer withheld too little tax all year, you will arrive at Tax Day already in debt to the IRS, compounding your financial stress.

Mistake 4: Using the Wrong Name or Social Security Number

This is a simple administrative error that causes massive delays. If you change your name after the divorce, the name on your tax return must match the name on file with the Social Security Administration (SSA).

If you file your tax return with your new name before you have officially notified the SSA, the IRS e-file system will reject your return. This can delay your tax refund for months.

The correct process is: 1) Legally change your name with the court, 2) Immediately notify the Social Security Administration, and 3) After the SSA confirms the change, file your tax return with your new name. If the tax deadline is near and the SSA has not processed your change, you must file using your old (married) name to avoid rejection.

Part 2: Asset Division Landmines (Why $1 Million is Not $1 Million)

This is the section where multi-thousand-dollar errors are made. The core principle is that not all assets are created equal.

Mistake 5: Ignoring the “After-Tax Value” of Assets

The most devastating mistake in a divorce settlement is creating a “fair” division of assets based on their market value. A $1 million cash account and a $1 million investment property are not financially equal.

One asset (cash) has zero tax due. The other (property) has a hidden “tax time-bomb” attached to it. Let’s look at a case study.

A couple has two assets to divide:

A cash bank account: $1,000,000
An investment property: $1,000,000

The property was purchased years ago for $300,000. This original purchase price is called the “tax basis.” The difference between the $1M value and the $300k basis is a $700,000 embedded capital gain.

Spouse A takes the $1M in cash. Spouse B takes the $1M investment property. It looks perfectly 50/50.

But when Spouse B sells that property, they are hit with a massive tax bill on that $700,000 gain. Assuming a 23.8% combined federal capital gains rate, the tax bill is $166,600. The true value of Spouse B’s asset was only $833,400. This is a catastrophic, unforced error. A smart settlement would have “tax-effected” the property, subtracting the future tax bill before dividing it.

Mistake 6: Misunderstanding “Carryover Basis” (The § 1041 Trap)

This is the legal mechanism behind Mistake 5. IRC § 1041 states that when an asset is transferred in a divorce, it is treated like a gift. No tax is due at the time of the transfer.

But the rule has a second part: the person receiving the asset also receives the original tax basis of the person who gave it to them. This is called a “carryover basis.”

This is not a tax-free transfer; it is a tax-deferred transfer. The person transferring the appreciated asset (like stocks or property) successfully transfers their tax liability to their ex-spouse. The recipient is the one who gets the full tax bill for all the appreciation that happened during the marriage.

Mistake 7: Botching the Sale of the Marital Home (The § 121 Trap)

This is one of the highest-value mistakes in any divorce. Under IRC § 121, a taxpayer can exclude a large amount of profit (capital gain) from the sale of their primary residence. You must have both owned the home and lived in it for at least two of the last five years.

Here is the financial trade-off:

Married couples filing jointly can exclude $500,000 of gain.
Single filers can only exclude $250,000 of gain.

The common mistake is driven by emotion. One spouse “fights for the house” and agrees to buy out the other. Years later, when they sell the house as a “Single” filer, they are shocked to discover they can only exclude $250,000 of gain. They have forfeited the other $250,000 exclusion they would have received if the couple had sold the home together while still married.

There is an advanced legal fix for this. The divorce decree can be written to state that the “out-spouse” (who moved out) is still allowed to count the “in-spouse’s” (who stayed) time in the home as their own. This is allowed under IRC § 121(d)(3)(B). When the home is sold years later, both ex-spouses can each claim their $250,000 exclusion, preserving the full $500,000 benefit even after the divorce.

Scenario 1: The Marital Home Sale

Timing of Sale	Financial Consequence
*Sell Before* the Divorce is Final**	Best Option. The couple files as “Married Filing Jointly” one last time. They can exclude up to $500,000 of profit from the sale, tax-free.
One Spouse Keeps, Sells Later	The Trap. The spouse who kept the house files as “Single.” They can only exclude $250,000 of profit. The other $250,000 exclusion from their ex-spouse is lost forever.
The Advanced Legal Fix	The Solution. The divorce decree includes specific language from IRC § 121(d)(3)(B). This allows the “out-spouse” to retain their exclusion. When the house is sold later, each ex-spouse can claim $250,000, saving the full $500,000 benefit.

Mistake 8: Forgetting to Divide “Invisible” Tax Assets

Marital assets are not just things you can touch. They also include “invisible” tax attributes that have real cash value. These are often forgotten in negotiations.

These assets include:

Capital Loss Carryforwards: If you had a bad year in the stock market, you might have losses you can use to offset future gains. This is a valuable asset.
Net Operating Losses (NOLs): If a business lost money, that loss can be carried forward to reduce future income tax.
Charitable Contribution Carryforwards: If you donated more than you could deduct, that remainder can be used in future years.

If your divorce agreement is silent on these items, they typically default to the spouse who generated them, even if they were on a joint return. This must be calculated and divided in the settlement, just like a bank account.

Part 3: The Revolution in Support & Dependents (The TCJA Landmine)

In 2017, the Tax Cuts and Jobs Act (TCJA) fundamentally changed divorce tax law. Any advice you get from friends or family who were divorced before 2019 is not just outdated; it is dangerous.

Mistake 9: Following the Old Alimony Rules

This is the biggest legislative change. The TCJA reversed 75 years of tax law.

OLD RULE (Decrees before Dec. 31, 2018): Alimony was deductible for the person paying it and taxable income for the person receiving it.
NEW RULE (Decrees on or after Jan. 1, 2019): Alimony is NOT deductible for the payer and NOT taxable income for the recipient.

The new rule makes alimony “tax-neutral,” just like child support. This change eliminated the “tax subsidy” of divorce, where a high-earning payer (in a 37% bracket) got a bigger tax break than the tax bill paid by the lower-earning recipient (in a 22% bracket). This change makes alimony much more expensive for the person paying it.

The Modification Trap: If you have a “grandfathered” pre-2019 deductible agreement, be extremely careful. If you modify that agreement, you can be permanently dragged into the new (non-deductible) rules if the modification explicitly states the new tax law applies.

Provision	Pre-2019 Alimony (Old Rule)	Post-2019 Alimony (New Rule)
Payer’s Federal Tax	Deductible (“above-the-line”)	NOT Deductible
Recipient’s Federal Tax	Taxable Income	NOT Taxable Income
State Tax (The Catch!)	Most states followed the Fed rule.	Not all states conform. In California, alimony is still deductible for state tax, creating a confusing split return.

Mistake 10: Confusing Child Support and Alimony

This is simple: Child support has always been tax-neutral.

Child support is NOT deductible for the payer.
Child support is NOT taxable income for the recipient.

Before the TCJA, people tried to disguise child support as deductible alimony. The IRS has “recapture” rules to stop this. Today, the main confusion is simply knowing that under federal law, both forms of support are now treated the same: paid with after-tax dollars.

Mistake 11: Both Parents Claiming the Same Child

Only one person can claim a child as a dependent. If both parents try to claim the same child, the IRS will apply its “tie-breaker rules.”

Under these rules, the custodial parent automatically wins the right to claim the child. The IRS defines the custodial parent as the one with whom the child lived for the most nights during the year (183 nights or more).

If the child lived with both parents for an exactly equal number of nights (a true 50/50 split), the IRS tie-breaker rule gives the exemption to the parent with the higher Adjusted Gross Income (AGI).

Mistake 12: Believing Your Divorce Decree Overrides the IRS

This is the most common procedural mistake regarding children. Your divorce decree might state, “The non-custodial parent shall claim the child in even-numbered years.”

That document is 100% meaningless to the IRS. The IRS is not a party to your divorce.

By default, the custodial parent (most nights) has the 100% legal right to claim the child, every single year. The only way to legally transfer that right to the non-custodial parent is for the custodial parent to sign IRS Form 8332, Release/Revocation of Release of Claim to Exemption.

If the non-custodial parent files and claims the child (attaching only the divorce decree), the IRS will reject their claim, grant the exemption to the custodial parent, and send the non-custodial parent a bill for the adjusted tax.

Deep Dive: How to Use IRS Form 8332

Form 8332 is a short but powerful document. It is the only thing the IRS recognizes.

Who fills it out? The custodial parent (the one with whom the child lived the most nights).
Part I: Release of Claim to Exemption for Current Year. This is used for a one-time release. If you agree to let the non-custodial parent claim the child for just this year, you check this box and sign.
Part II: Release of Claim to Exemption for Future Years. This is the more common use. The custodial parent signs this to release the claim for a specific number of years (e.g., “all future even years”) or for all future years. This must be specific.
Part III: Revocation of Release of Claim. A custodial parent who signed Part II can revoke it. This section is used to take back the right for future years. This often leads to court battles, as it may violate the divorce decree.
What happens next? The custodial parent signs the form and gives it to the non-custodial parent. The non-custodial parent must attach a copy of this signed Form 8332 to their tax return every single year they claim the child.

Part 4: The Million-Dollar Retirement & Business Mistakes

These are high-net-worth errors where a single missing document or valuation error can cost a fortune.

Mistake 13: Believing Your Divorce Decree Can Split a 401(k)

This is a financial emergency waiting to happen. Your divorce decree cannot split a 401(k), 403(b), or pension plan.

To divide these specific “qualified” retirement plans, you must have a separate, special court order called a Qualified Domestic Relations Order (QDRO). A QDRO is a complex legal document that instructs the plan administrator (e.g., Fidelity, Vanguard) to create a new account for the ex-spouse (“alternate payee”).

Note: A QDRO is not needed to split an IRA. That can be done with a divorce decree under § 1041. This rule is only for ERISA-protected plans like 401(k)s.

Failing to file the QDRO is catastrophic. The divorce decree is worthless to the plan administrator.

Scenario 2: The Missing QDRO

Action Taken	Financial Consequence
QDRO Filed Promptly	The plan administrator “qualifies” the order and creates a separate account for the ex-spouse. The retirement funds are safe and legally theirs.
No QDRO Filed (The Trap)	The divorce is final, but no QDRO is submitted. The participant (ex-spouse) still legally controls 100% of the account.
The Nightmare Scenario	Years pass. Before the QDRO is filed, the participant (1) Retires and liquidates the 100% account , (2) Dies (the money goes to their named beneficiary, like a new spouse) , or (3) Remarries and their new spouse gains spousal rights. The original ex-spouse’s share is gone, and their only recourse is to sue their ex-spouse personally for the money, which is likely spent.

Deep Dive: The 5-Step QDRO Process

Do not wait. This should be done simultaneously with the divorce decree.

Step 1: Get Plan Documents. Your attorney must get the “Summary Plan Description” and any QDRO procedures from the plan administrator.
Step 2: Draft the QDRO. An attorney drafts the complex order. It must contain specific legal language required by the plan and federal law.
Step 3: Submit for Pre-Approval (CRITICAL). The draft QDRO is sent to the plan administrator before it goes to the judge. The administrator will review it and confirm they will accept it. This prevents the court from signing an order the plan will later reject.
Step 4: Get the Judge’s Signature. Once pre-approved, the QDRO is submitted to the court to be signed and entered as an official order.
Step 5: Send the Final Order. The certified copy of the signed QDRO is sent to the plan administrator, who then “qualifies” it and divides the account.

Mistake 14: Ignoring the “Embedded Tax” in a Business

For high-net-worth couples, a closely-held business is often the largest marital asset. As in Mistake 5, the “sticker price” is not the “real price.”

The mistake is valuing a $1 million C-Corporation the same as a $1 million S-Corporation. A C-Corporation faces “double taxation”: the business pays tax on its profits, and the owner pays tax again when those profits are distributed. An S-Corporation is a “pass-through” entity; profits are only taxed once on the owner’s personal return.

That $1 million C-Corp has a massive “embedded tax liability” that the S-Corp does not. The spouse who “keeps the business” may look like they won, but they may have just accepted a future tax bill worth hundreds of thousands of dollars that was never factored into the settlement. This requires a forensic accountant to value properly.

Part 5: Liability & Protection (The “Cover Your Back” Mistakes)

These mistakes are about protecting yourself from your ex-spouse’s financial actions, both past and present.

Mistake 15: Signing a Joint Return with a Distrusted Spouse

When you file as “Married Filing Jointly,” you are “jointly and severally liable” for 100% of the tax bill.

This means the IRS can come after you for the entire tax debt, interest, and penalties, even if the debt was created entirely by your spouse’s hidden income or fraudulent deductions.

Your divorce decree cannot protect you. The decree might say, “Spouse A is responsible for all 2023 tax debts.” The IRS does not care. They will seize your refund and garnish your wages, leaving you to sue your ex-spouse in civil court to get your money back.

If you are still married on Dec. 31 but you suspect your spouse is hiding income, do not sign the joint return. File as “Married Filing Separately” to create a legal firewall between you and their tax liability.

Scenario 3: The High-Conflict Tax Filing

Filing Status Chosen	Financial Consequence
Married Filing Jointly (MFJ)	The Risk. You get a lower tax bill this year. But you are now 100% legally responsible for your spouse’s secret income or fraudulent deductions. The IRS can pursue you for their debt forever.
Married Filing Separately (MFS)	The Shield. You pay a much higher tax rate this year and lose many credits. But you have built a legal firewall. The IRS cannot hold you liable for your spouse’s fraud on their separate return. This is a defensive, protective filing.

Mistake 16: Not Requesting “Innocent Spouse Relief”

What if it’s too late? What if you already signed a joint return years ago, and now the IRS is sending you a massive bill for your ex’s tax fraud?

You are not helpless. Your “recovery step” is to immediately file IRS Form 8857, Request for Innocent Spouse Relief. This form asks the IRS to forgive your portion of the debt.

There are three types of relief you can request on this one form :

Innocent Spouse Relief: This is the most complete. You must prove you filed a joint return with an understated tax, you “did not know, and had no reason to know” about the error, and it would be unfair to hold you liable.
Separation of Liability Relief: This allocates (splits) the tax debt. You are no longer jointly liable for 100%. You are only responsible for the part of the tax debt related to your income.
Equitable Relief: This is the catch-all. If you don’t qualify for the other two (perhaps you “had reason to know,” but were a victim of spousal abuse or financial control), you can ask for this. You argue that it would be “unfair” to hold you liable given all the facts and circumstances.

Deep Dive: How to File Form 8857 (Request for Relief)

Filing this form triggers a legal process. The IRS will notify your ex-spouse and give them a chance to participate and argue against your request.

Page 1 (General Info): You provide your information and check which tax years you are requesting relief for.
Part I (Type of Relief): You check the box for which of the 3 types of relief you are seeking. You can check all three.
Part II (Allocation): If you request “Separation of Liability,” you must go line by line through the tax return and allocate which income and deductions belong to you vs. your ex-spouse.
Part III (Your Situation): This is the most important part. You must answer “Yes” or “No” to critical questions like “Did you know…?” and “Were you a victim of abuse?”
Part IV (Your Statement): This is your story. You must attach a detailed, written statement explaining why you should get relief. Explain why you didn’t know about the error, why you had no reason to know (e.g., your spouse controlled all the finances), and why it would be unfair to make you pay. Attach supporting documents like divorce decrees or police reports if they help your case.

Mistake 17: Making Financial Decisions Based on Emotion

This is the “root cause” mistake that enables all the others. Divorce is a “steaming cauldron of emotions” driven by fear, anger, and guilt.

Emotion makes you “agree to a settlement just to get it over with.” Emotion makes you “fight for the house” even when you can’t afford it , causing you to fall into the $250k tax trap (Mistake 7). Emotion makes you want to “chase down $100” even if it costs “$1000 in legal fees” just to “win.”

This is the most expensive mistake of all. The solution is to build a team (a tax-savvy lawyer, a CPA, and a Certified Divorce Financial Analyst (CDFA)) whose only job is to be logical and protect you from these permanent, multi-thousand-dollar errors.

Part 6: Critical State Nuances & Strategic Plans

Federal law is only half the battle. Your state law controls how property is divided, which has massive tax implications.

Community Property vs. Equitable Distribution

The U.S. has two systems for dividing property:

Community Property States (like California, Texas, Arizona, Washington) : In these states, all assets and income acquired during the marriage are generally considered owned 50/50 by both spouses.
Equitable Distribution States (Most other states, like New York, Florida, Illinois) : Assets are divided “fairly” (equitably), but not necessarily “equally.” A judge can award 60/40 or 70/30 based on factors like the length of the marriage or each spouse’s earning potential.

This creates a major tax trap in community property states. If you file “Married Filing Separately,” you must still report 50% of your spouse’s income on your return, and they must report 50% of yours. This can be a shock to a lower-earning spouse who now has to pay tax on income they never personally received.

State Tax “De-Coupling”

Not all states follow the new federal tax laws. This is a critical trap.

The best example is California. Under the federal TCJA, alimony paid is NOT deductible. But California did not conform to this law. For state income tax, alimony IS still deductible for the payer and IS still taxable income for the recipient.

This means you must file two different returns: a federal return where the alimony is ignored, and a state return where it is reported. This makes tax preparation vastly more complex.

Pros and Cons: Filing Jointly vs. Separately (While Still Married)

If your divorce is not final by Dec. 31, you must choose MFJ or MFS. This is a major strategic decision.

Pros of…	Cons of…
Married Filing Jointly (MFJ)	Married Filing Jointly (MFJ)
1. Lower Tax: This status almost always results in the lowest combined tax bill.	1. 100% Liability: You are “jointly and severally liable” for 100% of the tax debt, including any fraud your spouse committed.
2. More Credits: You are eligible for key tax credits (like education credits) that are disallowed when filing separately.	2. Requires Cooperation: You must cooperate with a person you are in conflict with, sharing all financial documents.
3. Higher Deductions: You get a much higher standard deduction.	3. Refund Can Be Seized: If your spouse owes back taxes, child support, or student loans, the IRS can seize your entire joint refund to pay their debt.
4. Capital Loss Offset: You can use one spouse’s capital losses to offset the other spouse’s capital gains.	4. No Protection: A divorce decree stating your spouse will pay cannot protect you from the IRS.
5. Simpler (If Amicable): It is one return and a cleaner financial break if you trust your spouse.	5. Binding Election: You cannot amend from MFJ to MFS after the tax deadline has passed.
Married Filing Separately (MFS)	Married Filing Separately (MFS)
1. Total Liability Protection: This is a legal firewall. You are only responsible for the tax on your own income.	1. “The Penalty”: This is the worst tax status. The tax brackets are higher, and the standard deduction is lower.
2. No Cooperation Needed: You do not need your spouse’s signature or financial documents to file.	2. Lose Most Credits: You automatically lose eligibility for the Earned Income Credit, education credits, and others.
3. Protects Your Refund: Your tax refund cannot be seized to pay for your spouse’s separate debts.	3. Standard Deduction Trap: If one spouse itemizes their deductions (e.g., mortgage interest), the other spouse must also itemize and gets a $0 standard deduction.
4. Can Be Amended: You can amend from MFS to MFJ within three years if you later reconcile or agree it’s better.	4. Community Property Problem: In states like CA or TX, you may still have to report 50% of your spouse’s income.
5. Signals Non-Cooperation: This is the only safe choice in a high-conflict divorce where you suspect fraud or hidden income.	5. More Complex: It requires two separate returns and a clear division of income and deductions.

Divorce Tax Planning: Do’s and Don’ts

Do’s	Don’ts
DO get a “tax-effected” value for all assets. Ask “What is the after-tax value?”	DON’T ever assume an asset’s market value is its real value.
DO get a copy of the retirement “Summary Plan Description” before you negotiate.	DON’T believe your divorce decree is enough to split a 401(k). It is worthless without a QDRO.
DO sell the marital home before the divorce is final to use the $500k exclusion.	DON’T give up the right to claim your child without getting a signed Form 8332 in exchange.
DO file “Married Filing Separately” if you suspect your spouse is hiding income.	DON’T follow old alimony advice. The law completely reversed on Jan. 1, 2019.
DO update your Form W-4 with your employer within 10 days of the final divorce decree.	DON’T forget to divide “invisible” assets like capital loss carryforwards.

Part 7: Frequently Asked Questions (FAQs)

Q: Who claims the children on taxes after a divorce? No. The “custodial parent” (most nights) claims them by default. The non-custodial parent can only claim them if the custodial parent signs IRS Form 8332.

Q: My divorce decree says I can claim my child. Is that enough? No. The IRS does not recognize divorce decrees for this. You must get a signed Form 8332 from the custodial parent and attach it to your return.

Q: I pay alimony. Can I deduct it on my taxes? No. If your divorce agreement was finalized after December 31, 2018, alimony is not deductible for the payer or taxable to the recipient under federal law.

Q: I receive alimony. Do I have to pay taxes on it? No. For agreements finalized after December 31, 2018, alimony is not considered taxable income on your federal return. (Check your state, as rules like California’s may differ ).

Q: Can I deduct my divorce attorney fees? No. Legal fees for getting a divorce are considered a personal expense and are not tax-deductible.

Q: We sold our house while married. How much profit is tax-free? Yes. If you file jointly and meet the 2-of-5-year ownership and residency rules, you can exclude up to $500,000 in capital gains from the sale of your primary home.

Q: I kept the house and sold it. How much profit is tax-free? Yes. As a single filer, you can exclude up to $250,000 in capital gains, provided you meet the 2-of-5-year ownership and residency rules.

Q: I filed the wrong status last year. Can I fix it? Yes. You can file Form 1040-X, Amended U.S. Individual Income Tax Return, to correct your filing status. You can amend from MFS to MFJ, but not from MFJ to MFS after the deadline.

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