Federal Insurance Contributions Act (FICA) Calculator
Last reviewed: December 2025. This calculator is reviewed annually to reflect current federal tax rules and thresholds.
The Federal Insurance Contributions Act (FICA) governs the payroll taxes that fund two cornerstone U.S. social programs: Social Security and Medicare. These taxes are automatically withheld from wages for most employees and represent a significant portion of federal payroll deductions.
Unlike income tax, FICA taxes are calculated independently of deductions, credits or filing adjustments. They apply directly to earned income and are assessed using fixed percentage rates, with specific rules for wage limits and high-income thresholds. Understanding how FICA works is essential for accurately interpreting paychecks, verifying withholding and planning for changes in income.
This FICA Calculator provides a combined view of your Social Security tax and Medicare tax obligations, allowing you to see how each component contributes to your total payroll tax for the selected tax year.
What Is FICA?
FICA is a federal payroll tax system established in 1935 to fund Social Security benefits and later expanded to support Medicare. These programs provide income support for retirees, disability benefits for eligible workers and healthcare coverage for seniors and qualifying individuals.
For employees, FICA taxes are withheld automatically from wages. Employers are required to contribute matching amounts, but this calculator focuses on the employee portion only.
FICA Tax Components
FICA consists of two separate taxes that behave very differently as income increases:
- Social Security tax: Applies only up to an annual wage base limit.
- Medicare tax: Applies to all earned income, with an additional surtax at higher income levels.
Because of these differences, FICA withholding does not increase uniformly as income rises, which often causes confusion when reviewing payroll deductions.
Social Security vs Medicare
Social Security tax is capped annually, meaning earnings above the wage base are no longer subject to Social Security withholding. Medicare tax, by contrast, continues to apply to every additional dollar earned.
High-income earners may also be subject to Additional Medicare Tax, which applies only above specific income thresholds and is not matched by employers.
Common FICA Misunderstandings
- Assuming FICA stops entirely once the Social Security cap is reached
- Confusing employer-paid taxes with employee withholding
- Overlooking Additional Medicare tax on higher earnings
- Expecting income tax deductions to reduce FICA liability
These misunderstandings can lead to incorrect expectations about take-home pay or year-end tax outcomes.
How This FICA Calculator Helps
This calculator estimates your combined employee FICA taxes by:
- Calculating Social Security tax up to the applicable wage base
- Applying Medicare tax to all eligible wages
- Identifying Additional Medicare tax where income thresholds are exceeded
- Presenting a clear breakdown of each component
It is especially useful for verifying payroll withholding, planning income changes, reviewing bonuses or understanding why withholding changes mid-year.
Scope and Related Tools
This calculator is intentionally focused on the employee portion of FICA taxes, providing a clear and accurate view of how Social Security and Medicare affect your personal take-home pay. Employer-paid payroll taxes are calculated separately under federal rules and are not deducted from employee wages, which is why they are excluded here.
If you need a broader payroll perspective or want to understand total employment costs, the following tools may be more appropriate:
- Use the Employer Payroll Costs Calculator to estimate employer-paid Social Security, Medicare and federal unemployment taxes.
- Use the Social Security Calculator or Medicare Calculator to analyse each FICA component independently.
- Use the Federal Tax Only Calculator to understand how payroll taxes interact with income tax and credits.
Together, these tools allow you to move from a focused payroll view to a complete federal tax picture, depending on how much detail you need.
For individual components, you can also use the dedicated Social Security Calculator or Medicare Calculator.
Related Calculators
Frequently Asked Questions
Can I estimate the General Business Credit?
Start with Form 3800 and then reflect the credit here.
How much would a 401(k) contribution change my net?
Model it with the 401(k) Calculator then rerun this page with your pre-tax amount.
Considering an IRS Offer in Compromise?
Read through Form 656-B to understand eligibility and steps.
What does FICA include?
FICA includes Social Security and Medicare payroll taxes withheld from employee wages.
Important Notes
All calculations are estimates for guidance only. Always review your return and consider professional advice when submitting official filings.