Every new Massachusetts employee needs to fill out an M-4. Employers need it to calculate state income tax withholding correctly. Here’s exactly how to complete it.
What Is the M-4?
The Massachusetts Employee’s Withholding Exemption Certificate (Form M-4) tells your employer how much Massachusetts state income tax to withhold from your paycheck. It’s the state equivalent of the federal W-4.
Massachusetts has a flat 5% income tax rate — so the M-4 doesn’t set your rate. What it sets is your exemption amount, which reduces the wages subject to that 5%.
When to Complete an M-4
- When starting a new job in Massachusetts
- When you want to change your withholding (more or fewer exemptions)
- When your personal situation changes (marriage, divorce, new dependent)
If you don’t submit an M-4, your employer must withhold as if you have zero exemptions — which means maximum withholding.
The M-4 Line by Line
Personal Information (top section)
Fill in your full name, home address, Social Security number, and filing status.
Filing status options:
- Single — unmarried, or married filing separately
- Married — married filing jointly (or qualifying surviving spouse)
- Head of Household — unmarried with a qualifying dependent
Filing status affects your federal withholding (W-4) more than your M-4 — the M-4 exemptions are the main variable for state withholding.
Line 1: Personal Exemption
Enter 1 if you are not claimed as a dependent on someone else’s return. Enter 0 if you are a dependent (typically full-time students claimed by parents).
Each exemption reduces your taxable wages by $1,000 per year ($38.46 per biweekly pay period, $41.67 monthly, etc.).
Most employees enter 1 here.
Line 2: Spouse Exemption
Enter 1 if your spouse has no income and you are not filing separately. Enter 0 if your spouse works (their employer will handle their own exemptions).
Most employees with a working spouse enter 0 here.
Line 3: Blindness Exemption
Enter 1 if you are legally blind. Enter 0 otherwise.
Line 4: Blindness Exemption for Spouse
Enter 1 if your spouse is legally blind. Enter 0 otherwise.
Line 5: Age 65+ Exemption
Enter 1 if you will be 65 or older before January 1 of the tax year. Enter 0 otherwise.
Line 6: Age 65+ for Spouse
Enter 1 if your spouse will be 65 or older before January 1 of the tax year and has no income.
Line 7: Dependents
Enter the number of qualifying dependents you claim — typically children or other family members for whom you’re legally responsible. Each dependent reduces your taxable wages by $1,000/year.
Example: Two qualifying children → enter 2.
Line 8: Total Exemptions
Add lines 1 through 7. This is your total number of exemptions.
A single employee with no dependents typically has 1 total exemption. A married employee with two children might have 2–4 depending on their situation.
Line 9: Additional Withholding
If you want extra Massachusetts income tax withheld each pay period (for example, to avoid a balance due at filing), enter a dollar amount here. This is optional.
When to use Line 9:
- You have freelance or rental income not subject to withholding
- You had an unexpected tax bill last year
- Your spouse has significant income at a higher effective rate
Signature
Sign and date the form. It’s not valid without a signature.
Common Questions
What if I claim too many exemptions? You’ll have less withheld during the year and may owe Massachusetts income tax when you file your return. You may also owe a penalty if you underpay significantly.
What if I claim too few exemptions? More is withheld from each paycheck. You’ll likely get a refund — but you’ve given the state an interest-free loan all year.
Can I claim “exempt” from Massachusetts withholding? Yes, if you had no Massachusetts tax liability last year and expect none this year. Write “exempt” on Line 8 instead of a number. This is rare — most employees don’t qualify.
Do I need to file a new M-4 every year? No — unlike the federal W-4, the M-4 stays in effect until you change it. But review it when your situation changes.
What does my employer do with it? They keep it on file and use your exemption number to calculate withholding. They don’t send the M-4 to the state (unlike W-2s at year-end).
Sample Completed M-4s
Single employee, no dependents:
- Line 1: 1
- Lines 2–7: 0
- Line 8: 1
- Line 9: blank
Married, two kids, spouse also works:
- Line 1: 1 (your personal exemption)
- Line 2: 0 (spouse has income)
- Lines 3–6: 0
- Line 7: 2 (two dependents)
- Line 8: 3
- Line 9: blank (or add extra if concerned about joint liability)
Single, age 67, no dependents:
- Line 1: 1
- Lines 2–4: 0
- Line 5: 1
- Lines 6–7: 0
- Line 8: 2
How Employers Calculate MA Withholding
Once you have the M-4, the employer calculates:
- Taxable wages = gross pay − pre-tax deductions
- Per-period exemption = $1,000 × total exemptions ÷ pay periods per year
- Adjusted wages = taxable wages − per-period exemption
- MA withholding = adjusted wages × 5%
Example: $2,500 biweekly gross, 1 exemption, no pre-tax deductions:
- Per-period exemption: $1,000 ÷ 26 = $38.46
- Adjusted wages: $2,500 − $38.46 = $2,461.54
- MA withholding: $2,461.54 × 5% = $123.08
The OtterDesk payroll calculator uses your M-4 exemption count to calculate Massachusetts state withholding accurately for any pay frequency.