Medicare & Social Security Tax: Complete 2025 Guide

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Meta Description: Complete breakdown of Medicare tax (1.45%/2.9%), Social Security tax (6.2%/12.4%), additional Medicare tax, and state disability insurance in 2025.

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        "text": "SDI (State Disability Insurance) is a California payroll tax of 1.1% in 2025 that funds short-term disability and paid family leave benefits. Employees pay this tax through payroll deduction. The tax applies to wages up to $153,164 annually. Only California, Hawaii, New Jersey, New York, and Rhode Island have state disability insurance programs."
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H1

What Is Medicare Tax and How Does It Work?

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ANSWER SECTION

Medicare tax is a 1.45% payroll tax assessed on all earned income with no wage cap. Both employees and employers pay 1.45% each, totaling 2.9% for self-employed individuals. Unlike Social Security tax, which stops at an annual wage base limit, Medicare tax applies to every dollar you earn. In 2025, high earners face an additional 0.9% Medicare tax on wages exceeding $200,000 for single filers or $250,000 for married couples filing jointly. These taxes fund the Medicare hospital insurance program (Part A) that provides health coverage for Americans aged 65 and older.

The Medicare tax system has operated since 1966 alongside Social Security taxes (FICA). While Social Security faces funding challenges due to its wage cap, Medicare taxes on all earned income provide a broader funding base. Understanding how Medicare tax works helps you calculate your true tax burden and plan for retirement healthcare costs.

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Medicare Tax Rates and Calculation

Standard Medicare Tax

The standard Medicare tax rate has remained consistent for decades:

Taxpayer Type	Medicare Tax Rate	Payment Method
Employee	1.45%	Withheld from paycheck
Employer	1.45%	Paid by employer, not visible on paycheck
Self-employed	2.9%	Paid through quarterly estimated taxes

Key Characteristics:

• No wage cap: Applies to all earned income regardless of amount
• No deduction: Self-employed individuals pay on net earnings but can deduct the employer-equivalent portion
• All earnings included: Wages, tips, bonuses, and self-employment income

Example Calculation

An employee earning $150,000 annually:

Component	Amount
Gross wages	$150,000
Employee Medicare tax (1.45%)	$2,175
Employer Medicare tax (1.45%)	$2,175
Total Medicare tax paid	$4,350

A self-employed individual with $150,000 net earnings:

Component	Amount
Net self-employment earnings	$150,000
Medicare tax (2.9%)	$4,350
Deductible portion (employer half)	($2,175)
Net tax cost after deduction	$2,175

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Additional Medicare Tax for High Earners

Income Thresholds

The Affordable Care Act introduced an additional Medicare tax of 0.9% for high-income taxpayers in 2013. This tax remains in effect for 2025:

Filing Status	Threshold Amount
Single	$200,000
Married Filing Jointly	$250,000
Married Filing Separately	$125,000
Head of Household	$200,000

How the Additional Tax Works

Employer Withholding:

• Employers must withhold the additional 0.9% once employee wages exceed $200,000 in a calendar year
• This applies regardless of the employee's actual filing status
• Married employees may have excess withholding if combining incomes stays under $250,000

Self-Employment:

• Self-employed individuals calculate additional Medicare tax on net earnings
• Combined wages and self-employment income count toward the threshold

Combined Rate Example

A single filer earning $300,000:

Income Level	Medicare Rate	Tax Amount
First $200,000	1.45%	$2,900
Amount over $200,000 ($100,000)	2.35% (1.45% + 0.9%)	$2,350
Total Medicare tax		$5,250

For the complete definition and basic explanation, see our guide on what is Medicare tax with rate breakdowns.

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Social Security Tax (FICA)

Social Security Tax Rates

Social Security tax funds retirement, disability, and survivor benefits:

Taxpayer Type	Rate	Applies To
Employee	6.2%	Wages up to wage base limit
Employer	6.2%	Wages up to wage base limit
Self-employed	12.4%	Net earnings up to wage base limit

2025 Wage Base Limit

The Social Security wage base increases annually with average wages:

Year	Wage Base Limit
2024	$168,600
2025	$176,100
2026	Indexed to wage growth

Once you earn $176,100 in 2025, you stop paying Social Security tax for the remainder of the year. This creates a noticeable increase in take-home pay for high earners mid-year.

Maximum Social Security Tax

Taxpayer Type	Maximum Tax (2025)
Employee	$10,918.20 ($176,100 × 6.2%)
Employer	$10,918.20
Self-employed	$21,836.40 ($176,100 × 12.4%)

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Medicare Premiums and Tax Deductions

Deductibility Rules

Medicare premiums receive different tax treatment depending on your employment status:

Employment Status	Deduction Method	Requirements
Self-employed	Above-the-line deduction (Form 1040 Schedule 1)	None — fully deductible
W-2 employee (itemizing)	Itemized medical expense (Schedule A)	Exceed 7.5% of AGI
W-2 employee (standard deduction)	Not deductible	N/A
Retired	Itemized medical expense (Schedule A)	Exceed 7.5% of AGI

Premium Amounts 2025

Part	Monthly Premium	Deductible?
Part A (Hospital)	$0 (if worked 40+ quarters)	N/A
Part B (Medical)	$185.00 (standard)	Yes, if requirements met
Part D (Prescription)	Varies by plan (~$55 avg)	Yes, if requirements met
Part C (Medicare Advantage)	Varies by plan	Yes, if requirements met

Note: Part B premiums increase for high-income beneficiaries through IRMAA (Income-Related Monthly Adjustment Amount).

For complete details on deducting Medicare premiums, see our guide on are Medicare premiums tax deductible with self-employment rules.

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IRMAA: Medicare Premium Surcharges

Income-Related Monthly Adjustment Amount

High-income Medicare beneficiaries pay higher Part B and Part D premiums:

Individual Income	Joint Income	Part B Premium (2025)	Part D Surcharge
≤$106,000	≤$212,000	$185.00	$0
$106,001-$133,000	$212,001-$266,000	$259.00	$12.90
$133,001-$167,000	$266,001-$334,000	$370.20	$33.30
$167,001-$200,000	$334,001-$400,000	$481.40	$53.80
$200,001-$500,000	$400,001-$750,000	$592.00	$74.20
>$500,000	>$750,000	$629.00	$81.00

Income Determination: IRMAA uses your modified adjusted gross income from two years prior (2023 income for 2025 premiums). Life-changing events like marriage, divorce, death of a spouse, or work reduction may qualify you for an appeal.

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State Disability Insurance (SDI)

California SDI Tax

California imposes an additional payroll tax for disability insurance:

Feature	2025 Amount
SDI tax rate	1.1%
Wage cap	$153,164
Maximum annual tax	$1,684.80
Employee-paid only	Yes

For the complete SDI rules, see our guide on what is SDI tax with benefit calculation details.

States With Disability Insurance Programs

Only five states have mandatory disability insurance programs:

State	Program Name	Employee Tax?
California	SDI (State Disability Insurance)	Yes, 1.1%
Hawaii	TDI (Temporary Disability Insurance)	Varies by employer
New Jersey	TDI/FLI	Yes, 0.47%
New York	DBL/PFL	Yes, varies
Rhode Island	TDI	Yes, 1.1%

For California-specific rules, see our guide on SDI tax with rate and benefit information.

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Disability Benefits and Taxation

Social Security Disability Insurance (SSDI)

SSDI benefits may be taxable depending on your total income:

Filing Status	Taxable if Provisional Income Exceeds
Single	$25,000
Married Filing Jointly	$32,000

Provisional Income Calculation: Adjusted Gross Income + Nontaxable Interest + 50% of SSDI Benefits

Taxability Levels:

• Below threshold: 0% taxable
• $25,000-$34,000 single ($32,000-$44,000 MFJ): Up to 50% taxable
• Above $34,000 single ($44,000 MFJ): Up to 85% taxable

For complete SSDI tax rules, see our guide on are disability benefits taxable with calculation examples.

Supplemental Security Income (SSI)

SSI benefits are NEVER taxable. This needs-based program provides assistance to disabled and elderly individuals with limited resources, and the benefits remain entirely tax-free.

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Self-Employment Tax Considerations

Calculating Self-Employment Tax

Self-employed individuals pay both the employee and employer portions:

Step 1: Calculate net earnings from self-employment Step 2: Multiply by 92.35% (to account for the employer half being deductible) Step 3: Apply Social Security tax (12.4%) up to wage base Step 4: Apply Medicare tax (2.9%) on all earnings Step 5: Apply additional Medicare tax (0.9%) if over threshold

Example for $200,000 Self-Employment Income

Calculation	Amount
Net self-employment earnings	$200,000
Multiply by 92.35%	$184,700
Social Security tax ($176,100 × 12.4%)	$21,836.40
Medicare tax ($184,700 × 2.9%)	$5,356.30
Additional Medicare tax ($184,700 - $200,000 threshold = $0)	$0
Total self-employment tax	$27,192.70
Deductible employer portion (50%)	($13,596.35)

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FAQ

Do I pay Medicare tax on investment income? No, Medicare tax applies only to earned income (wages and self-employment earnings). However, the Net Investment Income Tax (NIIT) of 3.8% applies to investment income for high earners above $200,000 (single) or $250,000 (MFJ).

Can I opt out of Medicare tax? No, Medicare tax is mandatory for all earned income. Even retirees working part-time continue paying Medicare tax on wages. Certain religious groups with established opposition to insurance may file Form 4029 for exemption, but this is rare.

Does Medicare tax qualify for a tax credit? No, Medicare tax payments are not credits. They are payroll taxes that fund the Medicare program. However, self-employed individuals can deduct the employer-equivalent portion (half of self-employment tax) as an adjustment to income.

What happens to Medicare taxes I have paid? Your Medicare taxes fund the Hospital Insurance (HI) Trust Fund, which pays for Medicare Part A benefits (hospital coverage). Unlike Social Security, you do not need 40 quarters of work to qualify for Medicare — you can buy into the program if needed.

Do non-resident aliens pay Medicare tax? Non-resident aliens on F-1, J-1, M-1, or Q visas are generally exempt from FICA taxes (including Medicare) for their first five calendar years in the U.S. Other non-residents may be subject to the taxes depending on treaty status and visa type.

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Related Resources

• What Is Medicare Tax? — Definition and basic rates
• Are Medicare Premiums Tax Deductible? — Self-employment and itemized deduction rules
• What Is SDI Tax? — California disability insurance explained

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