FICA taxes explained for part-time workers
FICA taxes explained for part-time workers, with a worked example, a checklist and the mistakes to avoid.
Why this matters for part-time workers
Part-time workers may be over-withheld or have several employers, so checking the numbers can uncover a refund.
Worked example
Here is the calculation with sample figures. Change any number in the FICA Tax Calculator to run your own.
| Gross annual salary | $135,000.00 |
| Social Security wage base | $184,500.00 |
| Social Security and Medicare | $10,327.50 |
|---|---|
| Net amount | $124,672.50 |
FICA taxes: how it works
FICA funds Social Security and Medicare. Employees pay 6.2% Social Security up to the wage base and 1.45% Medicare on all wages, plus 0.9% additional Medicare on high wages.
Employers match the 6.2% and 1.45%.
A second example with larger figures
Scaling the inputs up shows how the result moves. Percentages stay the same, so the tax grows in proportion to the amount it is applied to.
| Gross annual salary | $405,000.00 |
| Social Security wage base | $184,500.00 |
| Social Security and Medicare | $19,156.50 |
|---|---|
| Net amount | $385,843.50 |
Using the calculator step by step
- Open the FICA Tax Calculator.
- Enter your own figures on each numbered line.
- Set the rate to the one that applies to you. Defaults are examples, not advice.
- Read the result and the formula below it.
Key terms
- Marginal rate
- The rate applied to the next unit of income. It decides how much of a raise or a deduction you keep.
- Taxable income
- Income left after allowances and deductions, on which the tax rates are applied.
- Zero rate
- A rate of 0% on a taxable supply. Unlike an exemption, the seller can usually still reclaim tax on costs.
- Tax credit
- An amount subtracted directly from the tax bill, worth its full face value.
- Standard rate
- The rate that applies to most goods and services unless a specific reduced rate, zero rate or exemption applies.
A quick checklist for part-time workers
- Check the current wage base.
- Apply both rates.
- Check the additional Medicare threshold.
Common mistakes to avoid
- Applying Social Security tax above the wage base.
- Forgetting the 0.9% additional Medicare tax.
Run your own numbers. The FICA Tax Calculator updates as you type and shows the formula it uses.
Frequently asked questions
Why should part-time workers care about this?
Part-time workers may be over-withheld or have several employers, so checking the numbers can uncover a refund.
What is the quickest way to calculate it?
Use the FICA Tax Calculator: enter your figures and it shows the result and the formula.
Is this tax advice?
No. It is general information for planning. Rules differ by country and change over time, so confirm with your tax authority or a qualified adviser.
This article is general information for planning, not tax advice. Rates and rules change; confirm with your tax authority or a qualified adviser.