How to Fill Out Michigan Form 5121 (w/Examples) + FAQs

Michigan Form 5121, the City of Detroit Withholding Tax Schedule, is the schedule that every individual who had City of Detroit income tax withheld from wages, pensions, or other compensation must file with their City of Detroit Income Tax Return to claim credit for that withholding. You file it with Form 5118 (resident return), Form 5119 (nonresident return), or Form 5120 (part-year resident return) — never on its own.

If you skip Form 5121, the Michigan Department of Treasury will deny your withholding credit, even when your W-2 clearly shows Detroit tax taken out. According to Treasury’s annual processing data, more than 250,000 City of Detroit individual income tax returns are filed each year, and missing or mismatched Form 5121 entries are among the top three reasons returns get adjusted under the City Income Tax Act, MCL 141.601 et seq..

Here is what you will learn:

📄 What Form 5121 is, who must file it, and how it ties to Forms 5118, 5119, and 5120
🧾 Every box on the schedule explained in plain English, with sample entries
👥 Three full walkthroughs for a resident, a nonresident commuter, and a part-year resident
📬 How to file by mail, through Michigan Treasury Online (MTO), or with approved e-file software
⚠️ The most common mistakes that trigger Treasury notices and how to avoid them

What Form 5121 Is and Who Must File It

Form 5121 is the City of Detroit Withholding Tax Schedule. The form lists every W-2, 1099-R, or other wage statement that shows Detroit city income tax withheld during the tax year. The current revision is the 2025 tax year version, dated Rev. 04-25 at the bottom of the official PDF on the Michigan Treasury city tax forms page. Treasury updates the form each year, so always confirm the revision date before you start.

The form exists because the City of Detroit ended its own paper return system in 2017 and handed administration to the Michigan Department of Treasury under Public Act 506 of 2014. Treasury needs Form 5121 to match employer-reported withholding (from Form 5321, the City of Detroit Annual Reconciliation) against the credit you claim on your individual return. If the numbers do not match, Treasury freezes the refund and sends a correspondence audit letter.

You must file Form 5121 if any of these are true:

You are a Detroit resident filing Form 5118 with any city tax shown in Box 19 of a W-2 or on a 1099-R.
You are a nonresident filing Form 5119 because you worked inside Detroit city limits and your employer withheld Detroit tax.
You are a part-year resident filing Form 5120 because you moved into or out of Detroit during the year.
You received pension or retirement income with voluntary Detroit withholding reported on a 1099-R.

You do not file Form 5121 if you had no Detroit withholding at all — even if you owe Detroit tax. In that case you pay through Form 5118, 5119, or 5120 directly. The legal authority sits in MCL 141.664, which requires withholding agents to report city tax and gives the taxpayer the right to claim that credit only when properly substantiated.

Before You Start: Documents and Information You Need

Gather every piece of paperwork below before you open Form 5121. Missing even one item forces you to stop, request a duplicate, and risk missing the April 15 filing deadline set under MCL 141.664(1).

All W-2 forms for the year. You need the original (or a legible copy) of every W-2 because Form 5121 requires data from Boxes 1, 18, 19, and 20. If a W-2 is missing, request it from your employer or pull it from your IRS Wage and Income Transcript. Without it, Treasury cannot verify the withholding line.
All 1099-R forms with Detroit withholding. Pension administrators sometimes withhold Detroit tax voluntarily. The amount appears in the locality box. If you do not list it on Form 5121, you lose the credit.
Your Social Security Number and your spouse’s SSN. Treasury cross-checks SSNs against the W-2 file submitted by employers. A typo causes the credit to be denied.
Your residency status for each pay period. Detroit taxes residents at 2.4% and nonresidents at 1.2% under Detroit’s city ordinance. You need to know which rate applies to each W-2.
The percentage of work performed inside Detroit (nonresidents only). This number drives the Wage Allocation portion of Form 5119, which Form 5121 supports.
A copy of last year’s Form 5121. It speeds up data entry and helps spot employer name or EIN changes.
Your employer’s federal Employer Identification Number (EIN). Box B of every W-2. Treasury matches Form 5121 against employer filings using this number.
The locality name shown in Box 20 of each W-2. It must read DETROIT (or DET) for the withholding to count as City of Detroit tax. Other Michigan city names belong on a different return entirely.
Bank account and routing number if you want a direct-deposit refund through Form 5118, 5119, or 5120.
A printed or saved copy of the form instructions from the Michigan Treasury city tax forms page, since the instructions are released as a separate booklet each year.

Where to Get the Form and How to Access It

The only authoritative copy of Form 5121 lives on the Michigan Treasury city tax forms page. Treasury posts the fillable PDF in late January each year alongside the matching Form 5118, 5119, 5120, and the city instruction booklet.

You have three legitimate ways to obtain the form:

Download the official PDF directly from Treasury. This is the safest option because third-party PDFs sometimes lag behind annual revisions.
Use approved tax software. Vendors listed on the Michigan e-file software providers page build Form 5121 into their City of Detroit modules. The software auto-populates the schedule from W-2 entries.
Request a paper form by mail or phone. Call Treasury at 517-636-5829 or write to Michigan Department of Treasury, Lansing, MI 48929. Allow two to three weeks for delivery.

Do not use a photocopy of last year’s form. The barcode at the bottom encodes the tax year, and Treasury’s scanners will reject an outdated barcode. Always confirm the revision date in the bottom-left corner of page 1 reads the correct tax year before you write a single number.

The fillable PDF works in Adobe Acrobat Reader. It will not save data correctly in some web browsers’ built-in PDF viewers, so download it and open it in Acrobat first. If you e-file, the software handles the form behind the scenes and you never touch the PDF.

Step-by-Step: How to Fill Out Form 5121 Line by Line

Form 5121 is a one-page schedule with a header block and a five-column table. Each row of the table represents one W-2 or 1099-R that shows Detroit withholding. The walkthrough below treats every field as its own subsection so you cannot miss a box.

Filer’s First Name, Middle Initial, and Last Name

The header asks for the primary filer’s full legal name exactly as it appears on the matching City of Detroit return (Form 5118, 5119, or 5120). Type or print it in capital letters in the order First, Middle Initial, Last.

To answer, copy the name from your Social Security card. Use all caps. Do not use nicknames, hyphenate only when the SSA record is hyphenated, and do not include suffixes like JR on this line if the suffix lives in its own box on Forms 5118–5120.

For example, MARIA T LOPEZ writes her name as MARIA T LOPEZ across the three boxes.

A common edge case is a recent legal name change. If you changed your name after marriage and the SSA has the new name on file, use the new name. If SSA still has the old name, use the old name to avoid an SSN/name mismatch.

The most common mistake here is entering a married name before SSA records reflect the change. The direct consequence is a name-control mismatch that delays the refund by 8 to 12 weeks.

A common misconception is that Treasury can “figure it out” from the SSN alone. They cannot. The matching algorithm checks the first four letters of the last name plus the SSN.

Filer’s Full Social Security Number

This box asks for the primary filer’s nine-digit SSN. Treasury uses it to link Form 5121 to the city return and to the employer-reported W-2 file.

To answer, write nine digits with no dashes if the form fields auto-format, or with dashes (XXX-XX-XXXX) if the PDF leaves space. Always match the SSN on the city return.

For example, Maria writes 123-45-6789.

The edge case is an Individual Taxpayer Identification Number (ITIN) from the IRS. Treasury accepts an ITIN in this box for filers who cannot get an SSN.

The most common mistake is transposing two digits. The consequence is automatic refund denial because the SSN will not match the city return’s SSN.

A common misconception is that you can leave this blank if your spouse’s SSN is on the city return. You cannot — the filer’s SSN must appear here even on a joint return.

Spouse’s Full Social Security Number

This box appears only when filing jointly and asks for the spouse’s SSN.

To answer, enter the spouse’s nine-digit SSN exactly as it appears on the joint city return. Leave blank on a single return.

For example, Maria’s husband Jorge enters 987-65-4321.

An edge case arises when one spouse has an ITIN and the other has an SSN. List the SSN holder as the primary filer to simplify matching.

The common mistake is swapping the primary and spouse SSNs between Form 5121 and Form 5118. The consequence is that the W-2 attributed to the wrong spouse may be denied because the employer reported it under the other SSN.

A misconception is that married-filing-separately filers list the spouse here. They do not — leave blank if filing separately.

Column A — Employer’s Identification Number from W-2 Box (b)

Column A asks for the federal EIN of each employer or payer that withheld Detroit tax. The number lives in Box b of the W-2 or in the payer block of a 1099-R.

To answer, enter the nine-digit EIN in XX-XXXXXXX format. Use one row per W-2, even if you had two W-2s from the same employer.

For example, Maria’s employer EIN is 38-1234567.

An edge case is a successor employer mid-year — Treasury wants the EIN that actually issued each W-2, even if the company merged. List both EINs on separate rows.

The common mistake is copying the state ID from Box 15 instead of the federal EIN from Box b. The consequence is that Treasury cannot match the row to the employer’s Form 5321 reconciliation and denies the credit.

A misconception is that you can list a single combined row when you have two W-2s. You cannot — each W-2 needs its own line.

Column B — SSN Associated With This W-2

Column B identifies whose W-2 this is on a joint return.

To answer, enter the nine-digit SSN of the spouse who earned those wages. On a single return, this is always the filer’s SSN.

For example, on Maria and Jorge’s joint return, Maria’s W-2 row shows 123-45-6789 in Column B and Jorge’s W-2 row shows 987-65-4321.

An edge case is W-2s issued to a deceased spouse during the year of death — use the deceased spouse’s SSN, and attach the death certificate to the city return.

The common mistake is listing the same SSN on every row of a joint return. The consequence is that the lower-earning spouse’s withholding may be misallocated, leading to balance-due notices.

A misconception is that the SSN here can differ from Box (a) of the W-2. It cannot — Column B must match the SSN printed on the W-2.

Column C — Wages, Tips, and Other Compensation from W-2 Box 1

Column C reports the federal wages from Box 1 of each W-2. Treasury uses it as a sanity check against the locality wage figure.

To answer, copy the dollar amount from Box 1 of the W-2. Round to the nearest whole dollar (drop cents under 50, round up at 50 and above).

For example, Maria’s W-2 Box 1 reads $58,432.17, so she writes 58,432.

An edge case is a W-2 with no Detroit withholding but Box 1 wages — that W-2 does not belong on Form 5121 at all. List only W-2s with Detroit tax withheld.

The common mistake is entering Medicare wages from Box 5 instead of Box 1. The consequence is a wage mismatch that triggers a Treasury inquiry.

A misconception is that Column C should match the locality wages in Box 18. It usually does not — Box 18 reflects only the portion subject to Detroit tax.

Column D — Locality Wages from W-2 Box 18

Column D reports the wages actually subject to City of Detroit tax. This figure drives the credit calculation.

To answer, copy Box 18 from the W-2 — but only the row where Box 20 reads DETROIT or DET. If Box 18 is blank but Detroit tax was withheld, contact your employer for a corrected W-2c.

For example, Jorge’s Box 18 shows $45,000 of Detroit-source wages, so he writes 45,000.

An edge case is multiple Box 18 entries on one W-2 (some employers list two cities). Use only the Detroit row and ignore the other.

The common mistake is leaving Column D blank when Box 18 is empty even though Detroit tax was withheld. The consequence is that Treasury defaults the locality wages to zero and may deny part of the credit.

A misconception is that Column D and federal wages must be equal. They are equal only when 100% of the work was performed in Detroit at the city’s resident rate.

Column E — City of Detroit Tax Withheld from W-2 Box 19

Column E is the heart of Form 5121. It is the dollar amount you are claiming as a credit on Forms 5118, 5119, or 5120.

To answer, copy Box 19 from each W-2 where Box 20 reads DETROIT. Round to whole dollars. Add the column at the bottom and carry the total to the matching line on the city return.

For example, Maria’s W-2 Box 19 reads $1,402.37, so she writes 1,402.

An edge case is employer over-withholding — if the employer withheld at the resident rate (2.4%) but you were a nonresident, you still claim the full Box 19 amount here. Then you reconcile on Form 5119 to get a refund of the excess.

The common mistake is entering Michigan state withholding from Box 17 in Column E. The consequence is a denied credit and a refund offset, because Treasury can see the W-2 file and knows Box 19 holds zero.

A misconception is that voluntary additional withholding agreed with the employer goes on a separate line. It does not — it is part of Box 19 already.

Locality Name (Box 20) Verification

While not its own column on Form 5121, the Locality Name in W-2 Box 20 is the gatekeeper for every row. Treasury rejects rows where Box 20 is anything other than DETROIT, DET, or a recognizable Detroit code.

To answer this implicit field, audit each W-2 before transcribing. If Box 20 says something else (like HIGHLAND PARK), that withholding belongs on a different city’s return — not Form 5121.

For example, if Carlos has two W-2s — one with Box 20 DETROIT and one with Box 20 HAMTRAMCK — only the Detroit row goes on Form 5121.

An edge case is an employer who abbreviates the city name idiosyncratically. Confirm with the employer’s payroll department and request a corrected W-2c if needed.

The common mistake is including a non-Detroit Michigan city W-2. The consequence is that Treasury denies the credit and may forward the case to the correct city.

A misconception is that “Michigan” alone in Box 20 means Detroit. It does not — Box 20 must specifically identify Detroit.

Total Detroit Tax Withheld (Sum of Column E)

The bottom of the schedule asks for the sum of Column E, which becomes your withholding credit on the city return.

To answer, add every amount in Column E and write the total on the Total line at the bottom of Column E. Then transfer that total to the Tax withheld from Schedule W (Form 5121) line on Form 5118 (line 19), Form 5119 (line 22), or Form 5120 (line 24).

For example, Maria’s three rows in Column E total $3,206. She writes 3,206 on the Total line.

An edge case is a single W-2 with two different localities. Make sure the Detroit-only portion makes it into the Column E total.

The common mistake is forgetting to transfer the total to the city return, which leaves the withholding credit at zero. The consequence is a balance due that should have been a refund.

A misconception is that the total can include estimated payments. It cannot — estimated payments go on a different line of Forms 5118, 5119, or 5120.

Three Filled-Out Examples Using Real Scenarios

Scenario 1 — Maria, a Detroit Resident with One Employer

Maria Lopez lives at 1245 W. Grand Blvd. in Detroit and works full time at an auto-supplier in the city. Her single W-2 shows $58,432 in Box 1, $58,432 in Box 18, $1,402 in Box 19, and DETROIT in Box 20. She files Form 5118 and attaches Form 5121.

Form 5121 Field	What Maria Enters
Filer’s Name	MARIA T LOPEZ
Filer’s SSN	123-45-6789
Spouse’s SSN	(blank — single)
Column A — Employer EIN	38-1234567
Column B — SSN	123-45-6789
Column C — Box 1 Wages	58,432
Column D — Box 18 Locality Wages	58,432
Column E — Box 19 Detroit Tax	1,402
Total Column E	1,402

Scenario 2 — Carlos, a Nonresident Commuter

Carlos Rivera lives in Royal Oak but works in downtown Detroit. He worked 80% of his time inside Detroit and 20% remotely from home. His W-2 shows $92,000 in Box 1, $73,600 in Box 18 (the 80% Detroit-source portion), $883 in Box 19, and DETROIT in Box 20. He files Form 5119.

Form 5121 Field	What Carlos Enters
Filer’s Name	CARLOS J RIVERA
Filer’s SSN	222-33-4444
Spouse’s SSN	(blank — single)
Column A — Employer EIN	38-7654321
Column B — SSN	222-33-4444
Column C — Box 1 Wages	92,000
Column D — Box 18 Locality Wages	73,600
Column E — Box 19 Detroit Tax	883
Total Column E	883
Carries to Form 5119 line	22

Scenario 3 — Janet, a Part-Year Resident Who Moved Out of Detroit

Janet Brown lived in Detroit from January through June, then moved to Dearborn in July and kept the same Detroit-based employer. Her employer issued two W-2s — one at the resident rate and one at the nonresident rate. She files Form 5120 and lists both on Form 5121.

Form 5121 Field	What Janet Enters
Filer’s Name	JANET R BROWN
Filer’s SSN	555-66-7777
Row 1 — Column A EIN	38-9999111
Row 1 — Column C Box 1 Wages	34,000
Row 1 — Column D Locality Wages	34,000
Row 1 — Column E Detroit Tax (resident)	816
Row 2 — Column A EIN	38-9999111
Row 2 — Column D Locality Wages	32,500
Row 2 — Column E Detroit Tax (nonresident)	390
Total Column E	1,206

How to File the Completed Form

Form 5121 always travels with Form 5118, 5119, or 5120. You cannot mail or e-file it alone. The Michigan Department of Treasury offers three filing channels under Revenue Administrative Bulletin 2017-12.

Mail (paper). Send the completed Form 5121 stapled behind the city return and copies of every W-2 and 1099-R it references. Mail returns expecting a refund to Michigan Department of Treasury, Lansing, MI 48956. Mail returns with payment due to Michigan Department of Treasury, Lansing, MI 48929. There is no fee to file. Pay any balance by check made out to State of Michigan – Detroit. Keep the certified-mail receipt as proof of filing. Processing runs 10 to 14 weeks for paper.

Michigan Treasury Online (MTO). Use the MTO portal only for business-side reconciliation. Individuals cannot e-file Form 5118/5119/5120 directly through MTO; they must use approved software. There is no fee. Keep the confirmation PDF.

Approved e-file software. Use any vendor on the approved software developers list. The software bundles Form 5121 with the city return automatically. Pay any balance by direct debit, credit card (third-party fee applies), or paper check after e-filing. Processing typically runs 2 to 6 weeks. Save the e-file acknowledgment as proof of filing.

The deadline is April 15 following the tax year, the same as the federal and Michigan deadlines under MCL 141.664. If April 15 falls on a weekend or holiday, the deadline shifts to the next business day. An automatic extension follows the federal Form 4868 extension when filed timely, but it extends time to file, not time to pay.

What Happens After You File

Treasury logs the return, scans Form 5121, and runs an automated match against the W-2 file submitted by your employer through Form 5321, the City of Detroit Employer Annual Reconciliation. If every Column A EIN, Column B SSN, and Column E amount lines up, the credit posts and the refund issues.

If anything mismatches, Treasury sends a Correspondence Inquiry letter (often called a “letter audit”) asking for copies of the W-2s. Respond within 30 days to avoid having the credit denied outright. You can upload the response through the Treasury eService portal or mail it back with the original letter on top.

Refunds issue by paper check unless you elected direct deposit on the city return. Direct deposits typically arrive 7 to 10 days after Treasury approves the return; paper checks arrive in 3 to 4 weeks. Track status at Where’s My Refund using your SSN, tax year, AGI, and filing status.

Treasury keeps the right to adjust under MCL 141.687 for up to four years after filing. If they adjust the withholding credit, they will issue a Notice of Intent to Assess. You have 60 days to request an informal conference under MCL 205.21 before the assessment becomes final.

Mistakes to Avoid When Filling Out the Form

Listing a non-Detroit Michigan city W-2. Treasury denies the credit because Box 20 does not say DETROIT.
Copying state withholding (Box 17) into Column E. The credit gets zeroed out at matching.
Forgetting to transfer the Column E total to the city return. Your refund disappears even though Form 5121 is correct.
Using the state ID (Box 15) instead of the federal EIN (Box b). The row fails to match employer reconciliation data.
Reporting Medicare wages (Box 5) in Column C. Triggers a wage-mismatch inquiry.
Combining two W-2s into one row. Treasury cannot match the combined entry.
Leaving Column D blank when Box 18 is empty. Treasury defaults locality wages to zero and partially denies credit.
Mismatching SSNs between Form 5121 and Form 5118/5119/5120. Causes outright denial.
Filing Form 5121 alone without the parent return. Treasury treats the schedule as orphaned and discards it.
Using last year’s PDF. The barcode encodes the wrong tax year and the scanner rejects the form.
Omitting 1099-R Detroit withholding. Pension withholding is a credit you forfeit if not listed.
Failing to round to whole dollars consistently. Cent-level entries cause OCR misreads.

Do’s and Don’ts

Do’s

Do download the form fresh each year from the Michigan Treasury forms page so you get the right barcode.
Do match every Column A EIN against W-2 Box (b) character by character to pass the matching algorithm.
Do attach legible copies of every W-2 and 1099-R you list so Treasury has the source documents.
Do keep a personal copy of Form 5121, the W-2s, and the city return for six years, the audit window under MCL 141.687.
Do e-file when possible because the software prevents column-mismatch errors.
Do confirm the locality reads DETROIT in Box 20 before listing any W-2 row.

Don’ts

Don’t file Form 5121 by itself — it must accompany Form 5118, 5119, or 5120.
Don’t include W-2s that show no Detroit withholding; they do not belong on this schedule.
Don’t round one column to whole dollars and another to cents; pick whole dollars and stay consistent.
Don’t sign Form 5121 — only the parent city return needs a signature.
Don’t mail to the wrong Lansing PO Box; refund returns and payment returns go to different addresses.
Don’t ignore a Treasury inquiry letter; missing the 30-day window forfeits the credit.

Pros and Cons of Filing on Your Own vs. With Help

Pros of filing on your own

No preparer fee. Saves $150–$400 in preparer charges.
Full control over data entry. You see every box you complete.
Faster turnaround when you e-file with consumer software like the vendors listed on Treasury’s approved list.
Better understanding of the credit for future years.
Privacy — no third party handles your W-2s.

Cons of filing on your own

Higher error rate on Column D and Column E, the two columns most often flagged.
No professional shield against a Treasury inquiry under MCL 141.687.
Harder to handle part-year residency or multi-state W-2s without guidance.
No representation in an informal conference if Treasury proposes an assessment.
Easy to miss the difference between the resident (2.4%) and nonresident (1.2%) rates published by the City of Detroit Income Tax Division.

FAQs

Do I have to file Form 5121 if my W-2 already shows Detroit tax withheld?

Yes. The W-2 alone does not trigger the credit. Treasury requires Form 5121 attached to your Form 5118, 5119, or 5120 to release the withholding credit.

Can I file Form 5121 without filing a City of Detroit return?

No. Form 5121 is a schedule, not a standalone return. It must accompany Form 5118 (resident), 5119 (nonresident), or 5120 (part-year resident).

Do I list a W-2 that has Detroit wages but zero Detroit tax withheld?

No. Form 5121 reports only W-2s with Detroit tax actually withheld in Box 19. W-2s without Detroit withholding do not belong on this schedule.

Should I write the EIN with or without the dash in Column A?

Yes, use the dash. Format the federal EIN from Box (b) of the W-2 as XX-XXXXXXX to match Treasury’s matching format.

Do I put my SSN or my spouse’s SSN in Column B for my spouse’s W-2?

Yes, use your spouse’s SSN. Column B must match the SSN printed on that specific W-2, even on a joint return.

Is Box 18 (locality wages) the same as Box 1 (federal wages)?

No. Box 18 reports only the wages subject to Detroit tax, which is often less than Box 1 for nonresidents who work partly outside Detroit.

Do I include 1099-R pension withholding on Form 5121?

Yes. Voluntary Detroit withholding on a 1099-R goes on Form 5121 the same way W-2 withholding does.

Can I e-file Form 5121?

Yes. Approved software listed on the Treasury approved-software page e-files Form 5121 with the city return.

Do I need to attach copies of my W-2s to Form 5121?

Yes. Attach copies of every W-2 and 1099-R listed on the schedule so Treasury can verify the entries.

Is the deadline to file Form 5121 the same as the federal deadline?

Yes. It is April 15 under MCL 141.664, shifting to the next business day if April 15 falls on a weekend or holiday.

Does an extension on the federal return extend Form 5121?

Yes. A timely federal Form 4868 extends the City of Detroit return and Form 5121, but it does not extend time to pay any balance due.

Can I amend Form 5121 if I forget a W-2?

Yes. File an amended Form 5118, 5119, or 5120 with a corrected Form 5121 attached, marking the parent return as Amended at the top.

Do I sign Form 5121?

No. Form 5121 has no signature line. Only the parent return (Form 5118, 5119, or 5120) requires a signature.

What if Box 20 on my W-2 says something other than DETROIT?

No, do not list it. Only W-2s with DETROIT (or DET) in Box 20 belong on Form 5121; other Michigan cities have their own returns.

Will Treasury send me a copy of Form 5121 if I lose mine?

Yes. Request a transcript through the Treasury eService portal or call 517-636-5829 to receive a copy of your filed schedule.

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