The “Med” line on your paycheck is one of two things: the mandatory federal Medicare tax, or your share of an employer-sponsored health insurance premium. They share an abbreviation and nothing else. The Medicare tax is a percentage of your gross wages, so the dollar amount moves when your pay moves. A health insurance premium is a flat amount that stays the same every pay period. Once you know that, telling them apart takes about ten seconds.
How to Tell Which One You Have
Payroll systems label these lines inconsistently, which is why the question comes up so often. Some stubs spell out “Medicare Tax” or “FICA-Med” for the tax and “Medical Ins” or “MEDINS” for the insurance premium. Others print “Med” for both and leave you to sort it out.
The fastest check is math. Multiply your gross pay for the period by 0.0145. If the “Med” amount matches that result or comes very close, you’re looking at the Medicare tax. If the number doesn’t budge from paycheck to paycheck even when your hours or bonus pay change, it’s almost certainly your health insurance premium. Most stubs also group deductions into categories such as “Taxes” and “Benefits” or “Pre-Tax Deductions,” which is another giveaway.
If you’re enrolled in employer health coverage, you should see both deductions on every stub. If you see only one “Med” line, either your payroll system rolls FICA into a single line or you didn’t elect health insurance through your employer.
The Medicare Tax
Every W-2 paycheck has 1.45% taken out for Medicare, the federal health insurance program for people 65 and older and certain younger people with disabilities. Your employer pays a matching 1.45%, so 2.9% of your wages goes to Medicare in total.1Internal Revenue Service. Topic No. 751, Social Security and Medicare Withholding Rates You never see the employer’s half on your stub.
This tax is part of FICA, the Federal Insurance Contributions Act, which also includes Social Security tax at 6.2%. Together, your FICA withholding is 7.65% of gross wages. Social Security tax stops once your earnings hit $184,500 in 2026, but Medicare tax has no cap.2Internal Revenue Service. Publication 15 (2026), Employers Tax Guide Every dollar you earn, no matter how high your income climbs, gets the 1.45% deduction.
Your employer handles all of this automatically. You can’t opt out, negotiate it down, or defer it. A few narrow exceptions apply to nonresident alien students on F-1, J-1, or M-1 visas within their first five calendar years in the U.S., to students working for the school where they’re enrolled at least half-time, and to members of certain religious groups with IRS approval.3Internal Revenue Service. Foreign Student Liability for Social Security and Medicare Taxes If none of those describes you, the 1.45% is not optional.
The Extra 0.9% for High Earners
Once your wages from a single employer pass $200,000 in a calendar year, an additional 0.9% Medicare tax kicks in on every dollar above that line. Your employer is required to start withholding it at that point, regardless of your filing status.4Internal Revenue Service. Questions and Answers for the Additional Medicare Tax That brings your employee-side Medicare rate to 2.35% on wages above the threshold. Your employer does not match this surcharge.
Your actual liability, though, depends on your filing status: 0.9% on wages above $200,000 for single filers and heads of household, above $250,000 for married filing jointly, and above $125,000 for married filing separately. A dual-income couple where each spouse earns $150,000 won’t have anything extra withheld by either employer, but they owe the surcharge on $50,000 of combined income. If you expect to owe it and your employer won’t withhold enough, the IRS says you should either make quarterly estimated payments or file a new Form W-4 requesting additional income tax withholding to cover the gap.4Internal Revenue Service. Questions and Answers for the Additional Medicare Tax
The Health Insurance Premium
The other “Med” on your stub is your share of employer-sponsored health insurance. This one is voluntary. It only appears if you enrolled in coverage during open enrollment or after a qualifying life event, and the amount is fixed for the plan year unless you change your coverage.
How much depends on the plan you picked and how much your employer subsidizes. According to the most recent national survey, the average employee contribution in 2025 was about $120 per month for single coverage and $571 per month for family coverage.5KFF. 2025 Employer Health Benefits Survey Your number could be higher or lower depending on your employer’s contribution, the tier you chose, and whether you picked an HMO, PPO, or high-deductible plan.
One detail that trips people up: the per-paycheck deduction depends on your pay frequency, not your monthly premium. If you’re paid semi-monthly, that’s 24 paychecks a year, so divide your annual premium by 24. Biweekly is 26 paychecks, so divide by 26. The biweekly number will be slightly smaller per check even though the annual total is the same. Your benefits enrollment documents will confirm what you should be seeing.
Your W-2 at year-end also shows the total cost of your employer-sponsored health coverage in Box 12, Code DD. That figure includes both your share and your employer’s contribution, and it’s informational only. It doesn’t increase your taxable income.6Internal Revenue Service. Reporting Employer-Provided Health Coverage on Form W-2
Why Most Premiums Come Out Pre-Tax
Most employers run health insurance premiums through a Section 125 cafeteria plan, which means your premium is subtracted from your pay before taxes are calculated. The IRS treats qualified benefits under a cafeteria plan as exempt from federal income tax, Social Security tax, and Medicare tax.7Internal Revenue Service. FAQs for Government Entities Regarding Cafeteria Plans That triple exemption is what makes pre-tax premiums valuable.
Here’s how it plays out on a stub. Say you earn $5,000 gross per pay period and your health premium is $300 pre-tax. Your federal taxable wages drop to $4,700, and that’s the figure that eventually shows up in Box 1 of your W-2. Your Medicare wages (Box 5) and Social Security wages (Box 3) also drop to $4,700.8Internal Revenue Service. General Instructions for Forms W-2 and W-3 (2026) You save on every payroll tax.
The Medicare tax itself works differently. It’s calculated on your gross wages and doesn’t reduce your taxable income at all. Money out the door with no offsetting tax break.
If a Deduction Looks Wrong
If your Medicare tax withholding doesn’t match 1.45% of your gross pay, the most likely explanation is a rounding quirk in your payroll system, but it’s worth flagging with payroll or HR. Employers that fail to withhold the correct Medicare tax remain liable for the amount they should have withheld until the employee pays the tax, and they can face penalties on top of that.9eCFR. 26 CFR 31.3102-4 Special Rules Regarding Additional Medicare Tax Catching it early saves everyone a headache at year-end.
For health insurance premiums, compare the per-paycheck deduction against your enrollment confirmation. Divide your annual premium by the number of pay periods (24 for semi-monthly, 26 for biweekly, 52 for weekly). If the numbers don’t line up, contact HR. Payroll systems occasionally miscalculate after mid-year coverage changes or when pay frequencies shift, and correcting an error in January is far easier than unwinding twelve months of wrong deductions.