What Is Medicare Employee Additional Tax?
What Is the Additional Medicare Tax?
The Additional Medicare Tax is a 0.9% surtax that supplements the standard Medicare tax, introduced as part of the Affordable Care Act to help fund Medicare. While the base Medicare tax is 1.45% for employees (matched by employers), or 2.9% for the self-employed (both employee and employer parts), the Additional Medicare Tax only applies to specific types of earned income that exceed certain thresholds based on filing status.
This tax applies to Medicare wages (including most salaries, bonuses, tips, and fringe benefits), self-employment income, and RRTA (Railroad Retirement Tax Act) compensation. It does not apply to investment income such as interest, dividends, or capital gains; those are addressed separately by the Net Investment Income Tax. Only the portion of earned income that exceeds the threshold is subject to the 0.9% surtax rate. You can learn more about how Medicare fits into different coverage options by reading our guide on how to check if you have Medicare coverage.
Who Pays the Additional Medicare Tax and When?
You are liable for the Additional Medicare Tax if your combined Medicare wages, self-employment income, and/or RRTA compensation (including your spouse’s, if you file jointly) exceed the set income thresholds for your filing status in a given tax year. Determination of liability does not occur solely through payroll withholding; instead, the true tax owed is ultimately calculated and settled when you file your federal tax return. Be mindful that, depending on your scenario, you may have more tax due or get a refund based on actual income reported.
Income Thresholds by Filing Status
The IRS established set thresholds for the Additional Medicare Tax determined by your tax filing status. If your combined earned income from applicable sources goes over these amounts in a year, the 0.9% surtax applies to the excess:
| Filing Status | Threshold Amount |
|---|---|
| Married filing jointly | $250,000 |
| Married filing separately | $125,000 |
| Single | $200,000 |
| Head of household | $200,000 |
| Qualifying widow(er) with dependent child | $200,000 |
Thresholds are not adjusted for inflation and have remained unchanged in recent years. For joint filers, you and your spouse must combine your relevant income, and any overpayment or underpayment is reconciled when filing jointly. To decide which Medicare plans are best for your needs in the future, review Best Medicare Plan for Seniors in 2026: Top Choices.
How Employers Withhold the Tax
Under IRS rules, employers are obligated to begin withholding an additional 0.9% from your pay once your Medicare wages or RRTA compensation exceed $200,000 in a calendar year – regardless of your filing status or any outside income your employer is unaware of. Withholding begins in the pay period in which your wages surpass $200,000 and continues through the rest of the year. Importantly, employers are not required (and do not) match this additional tax, making it an employee-only burden.
Employees should note that employer withholding may not always perfectly match your final tax liability. This is especially true if you have multiple sources of employment or if your overall income with a spouse exceeds your filing threshold, even if no single employer pays you above $200,000. For guidance on enrolling for Medicare and understanding employer implications, consider reading Signing Up for Medicare for the First Time: Complete Guide.
Calculating the Additional Medicare Tax for Employees and the Self-Employed
Step 1: Calculate on Wages and RRTA Compensation Above the Threshold
Identify total wages subject to Medicare tax and, if applicable, RRTA compensation, and determine their sum for the tax year. Subtract your filing status threshold (see previous section). Any amount above the threshold is subject to the 0.9% Additional Medicare Tax.
Step 2: Reduce Threshold Amount for Self-Employment Income
If you have both wages and self-employment income, subtract your total Medicare wages from your filing threshold (but not below zero). Any remaining threshold applies to your net self-employment income. For any self-employment income above this reduced threshold, you also owe the 0.9% surtax-in addition to the regular self-employment (SE) tax.
Step 3: Special Rule for RRTA Compensation
If you receive both FICA (Federal Insurance Contributions Act) wages and RRTA compensation in the same year, apply your threshold separately to each. This prevents double taxation of the same income.
Step 4: Self-Employed Individuals’ Total Obligations
Self-employed filers pay both the employee (0.9%) and employer portions (1.45%) of Medicare tax on income exceeding their applicable threshold, resulting in a combined 2.35% tax rate above the limit after regular SE tax is considered. Accurately tracking your net self-employment income is crucial for Medicare surtax calculation. Those considering switching to a Medicare Advantage plan should consult How to Compare Medicare Advantage Plans Effectively for additional insight.
Example Calculations
- Single filer (C): C earns $130,000 in Medicare wages, which is below the $200,000 threshold-so no Additional Medicare Tax on wages is due. If C also earns self-employment income, the threshold for this is reduced to $70,000 ($200,000 threshold minus $130,000 wages).
- Married filing jointly (D & E): D earns $150,000 in wages (under $250,000 threshold). E has self-employment income, with a reduced threshold of $100,000 ($250,000 minus $150,000). Only E’s income above $100,000 is subject to the 0.9% tax.
- Married filing separately (F): F reports $175,000 in wages, exceeding the $125,000 threshold by $50,000. That excess incurs $450 in Additional Medicare Tax (0.9% x $50,000).
- Head of household (G): G has $225,000 in wages, surpassing the $200,000 threshold by $25,000, resulting in $225 owed.
- Single filer: With $300,000 in wages, this person pays tax on $100,000 (the amount over $200,000), for a $900 Additional Medicare Tax (0.9% x $100,000).
Reconciling the Additional Medicare Tax on Your Tax Return (Form 8959)
If your total Medicare wages, RRTA compensation, or self-employment earnings reach or exceed the relevant threshold, you must complete and attach Form 8959 to your Form 1040. This form is used to reconcile what your employer(s) withheld with your actual liability. If your employer withheld too little (or too much, common with multiple jobs or combined income with a spouse), the difference is settled via your return. Excess withholding is refunded to you.
The Form 8959 instructions provide a line-by-line guide to help filers calculate their correct Additional Medicare Tax, including accounting for situations with several employers or various forms of income. Tax software or professionals will often include prompts for entering relevant data. Guidance can also be found in IRS Publication 15, and those in California who want information on future Part D coverage should check out Medicare Part D Plans California 2026 Overview.
Tips for Multiple Employers or Spouses
- Multiple Employers: Each employer withholds the surtax only if your wages there exceed $200,000. If your combined income across jobs exceeds your filing status threshold, you may owe more, or you may have excess withheld. File Form 8959 to reconcile any differences and claim a refund if you overpaid.
- Spouses Filing Jointly: Combine all spouse wages and self-employment incomes to compare against the $250,000 threshold. One spouse’s wages decrease the other’s self-employment threshold. This is crucial for accurate Medicare surtax calculation and avoiding surprises at tax time.
- Withholding Adjustments: If you anticipate owing the tax, consider increasing your withholding via Form W-4 or make additional estimated tax payments to avoid underpayment penalties.
- Overpayment Examples: If a single filer earns $210,000 from one job, the employer withholds the surtax on $10,000, but if investment earnings put total income above another threshold, reconciliation still occurs in filing. Overpayments are refunded.
Resources and Where to Get Help
To avoid confusion and ensure full compliance with the recent IRS updates, refer to official IRS materials, including:
- IRS Publication 15 (Circular E), the Employer’s Tax Guide
- Form 8959 instructions for detailed filing help
- IRS.gov’s Topic No. 560: Additional Medicare Tax and Questions & Answers resources
Consulting reputable tax software or a qualified tax professional is highly recommended. For Medicare-specific questions, from original sign-up to ongoing plan management, see our comprehensive resources including how to check if you have Medicare and guidance on first-time Medicare sign-up.
