Medicare tax pays for hospital insurance, medical services, and prescription drug coverage

The Medicare tax you pay from your paycheck funds four specific insurance programs: Part A (hospital stays and skilled nursing), Part B (doctor visits and outpatient care), Part D (prescription drugs), and Part C (Medicare Advantage plans run by private insurers). The money does not sit in a personal account with your name on it. Instead, it flows into a shared trust fund that pays claims for everyone currently enrolled in Medicare, regardless of how much they paid in during their working years.

When you turn 65, you become may be able to access to draw from these same funds. The amount you receive in benefits is not tied to what you contributed — it depends on which parts you join and what services you use. Someone who paid Medicare tax for 40 years receives the same hospital coverage as someone who paid for 10 years, as long as both meet the age requirement.

Key Takeaways

  • Medicare tax funds hospital insurance (Part A), doctor and outpatient services (Part B), prescription drug coverage (Part D), and the infrastructure for private Medicare Advantage plans (Part C).
  • The tax is split between employee and employer: you pay 1.45 percent of wages, and your employer matches that amount, for a total of 2.9 percent.
  • Self-employed people pay the full 2.9 percent themselves, though they can deduct half of it on their tax return.
  • High earners pay an additional 0.9 percent Medicare tax on wages above $200,000 (single) or $250,000 (married filing jointly), with no employer match.
  • The money goes into a shared trust fund that pays current beneficiaries' claims; it is not saved in an individual account.

How the Medicare tax is split between you and your employer

If you are a W-2 employee, you and your employer each pay 1.45 percent of your gross wages into Medicare. You see the employee portion deducted from your paycheck; your employer sends their half directly to the Internal Revenue Service. Together, that is 2.9 percent of your salary funding the program.

If you are self-employed, you pay both halves yourself: 2.9 percent of your net self-employment income. When you file your tax return, you can deduct half of what you paid (1.45 percent) as a business expense, which lowers your taxable income. The other half remains a tax liability.

These base rates have been in place since 1966 and do not change year to year. What does change is the wage threshold for the additional tax on high earners.

The additional Medicare tax on high earners

If your wages exceed $200,000 in a single year (or $250,000 for married couples filing jointly), you pay an extra 0.9 percent Medicare tax on the amount above that threshold. This additional tax was introduced in 2013 as part of the Affordable Care Act. Unlike the base 1.45 percent, your employer does not match this extra amount — you pay it all.

The threshold does not adjust for inflation, so more people cross it each year as wages rise. If you have multiple jobs or are married and both spouses work, the thresholds explore to combined household income, not per-job income. Your employer withholds based on what they know about your wages at their company, so you may owe more when you file your tax return if your total income from all sources exceeds the limit.

Part A: Hospital insurance funded by Medicare tax

Part A covers inpatient hospital stays, skilled nursing facility care (up to 100 days per benefit period), hospice, and home health services. When you are admitted to a hospital, Part A pays the facility's costs after you meet your deductible, which changes each year. In 2024, the Part A deductible is $1,676 per benefit period.

Part A is automatic when you turn 65 if you have paid Medicare tax for at least 10 years (40 quarters). You do not pay a monthly premium for Part A coverage, though you do pay the deductible and coinsurance when you use it. The tax revenue funds these claims directly.

Part B: Doctor and outpatient services funded by Medicare tax and premiums

Part B covers doctor visits, lab tests, imaging, outpatient surgery, and preventive care. Unlike Part A, Part B is not automatic — you must enroll during your initial enrollment period or face a permanent penalty if you delay. Part B is funded partly by Medicare tax revenue and partly by monthly premiums you pay (the standard premium in 2024 is $164.90, though higher earners pay more).

Part B has a yearly deductible ($240 in 2024) and then covers 80 percent of approved services. You pay the remaining 20 percent, unless you have supplemental coverage. The combination of tax revenue and premiums keeps Part B solvent, though the balance between the two shifts as healthcare costs change.

Part D: Prescription drug coverage funded by premiums and general revenue

Part D is run by private insurance companies under contract with Medicare. Your monthly premium goes directly to your chosen plan, not into the Medicare tax fund. However, the federal government subsidizes Part D plans using general tax revenue, which includes Medicare tax. The subsidy covers roughly 75 percent of the program's costs; premiums and out-of-pocket spending by beneficiaries cover the rest.

Part D is optional, but if you do not join when you first become may be able to access, you pay a penalty for each month you delay (1 percent of the national average premium per month). The penalty is permanent and added to your premium for as long as you have Part D coverage.

Part C: Medicare Advantage plans and how they use Medicare tax revenue

Part C (Medicare Advantage) is an alternative to Original Medicare (Parts A and B). Private insurers offer these plans under contract with Medicare. The federal government pays each plan a fixed amount per enrollee per month, drawn from Medicare tax revenue and Part B premiums. In return, the plan must cover everything Part A and Part B cover, plus usually prescription drugs and dental or vision benefits.

You still pay a Part B premium if you join a Medicare Advantage plan, and many plans charge an additional monthly premium. Your out-of-pocket costs (deductibles, copays, coinsurance) are often lower than Original Medicare, but you are limited to the plan's network of doctors and hospitals. The Medicare tax revenue allocated to your plan is the same whether you use it heavily or not.

What happens to Medicare tax revenue that is not spent when ready

Medicare has two trust funds: the Hospital Insurance Trust Fund (Part A) and the Supplementary Medical Insurance Trust Fund (Parts B and D). Money collected from Medicare tax goes into these funds, and claims are paid out. When revenue exceeds spending, the surplus is invested in U.S. Treasury bonds. When spending exceeds revenue, the trust funds draw down their reserves and redeem those bonds.

The Part A trust fund has faced periods of projected depletion — most recently projected for 2031 — when reserves would run out and incoming tax revenue alone would cover only about 89 percent of claims. Congress has historically raised the tax rate, increased the wage cap, or adjusted benefits to prevent this. Part B and D are funded differently and do not face the same solvency crisis because premiums and general revenue adjust automatically.

Frequently Asked Questions

Can I opt out of paying Medicare tax?

No. Medicare tax is mandatory for all employees and self-employed people earning above a certain threshold. The only exception is members of certain religious groups (like the Amish) who have received an IRS exemption, and some government employees hired before 1983 who are covered by alternative pension systems.

Do immigrants and non-citizens pay Medicare tax?

Yes, if they work and earn wages in the United States. Undocumented immigrants who work using an Individual Taxpayer Identification Number (ITIN) pay Medicare tax but cannot draw Medicare benefits at 65 unless they later become citizens or permanent residents. Legal permanent residents and visa holders pay the tax and can receive benefits if they meet the 10-year work requirement.

What if I paid Medicare tax but did not work 10 years?

You do not automatically may have access to for Part A at 65. However, you can still enroll in Part B and Part D by paying premiums. Some people who did not work 10 years themselves but were married to someone who did can receive benefits based on their spouse's work record.

Does Medicare tax go into Social Security?

No. Medicare tax and Social Security tax are separate. Social Security tax is 12.4 percent (6.2 percent employee, 6.2 percent employer) and funds retirement, disability, and survivor benefits. Medicare tax is 2.9 percent and funds only Medicare. Both are withheld from your paycheck, but they fund different programs.

Why do high earners pay more Medicare tax?

The additional 0.9 percent Medicare tax on high earners was added in 2013 to help fund the Affordable Care Act and address the long-term solvency of Medicare. The threshold ($200,000 single, $250,000 married) has not changed since then, so more people are subject to it each year as wages rise.