Tax Withholding Calculator

Nobody's take-home pay matches their salary, and the gap is not one number but three: federal income tax withholding, Social Security, and Medicare, each calculated differently and none of them adjustable in the same way. This calculator models all three so you can see exactly where a paycheck goes before it ever gets to your bank account, and where the model has to simplify things a real W-4 handles a little differently.

How the Three Deductions Actually Work

Federal income tax withholding is an estimate of your annual tax bill, spread across your paychecks and adjusted by the filing status, allowances, and extra withholding you enter on Form W-4. It is progressive, different slices of your income are taxed at different rates, and it is the only one of the three deductions your W-4 can change.

Social Security (6.2%) and Medicare (1.45%, plus 0.9% more on wages above $200,000 for single filers) are flat-rate payroll taxes set by law. Nothing on your W-4 affects them; the only thing that changes your FICA withholding is your income itself, and Social Security stops applying entirely once you cross the annual wage base ($160,200 for 2024).

Worked Example: $75,000 Salary, Single, Paid Bi-Weekly

Using this calculator's defaults, $75,000 annual income, single filer, one allowance, no extra withholding, no pre-tax deductions, paid bi-weekly (26 paychecks), here is exactly how the numbers move:

• Taxable income: $75,000 − $13,850 (standard deduction) − $4,300 (one allowance) = $56,850
• Federal tax: 10% on the first $11,000 ($1,100) + 12% on the next $33,725 ($4,047) + 22% on the remaining $12,125 ($2,667.50) = $7,814.50
• Social Security: $75,000 × 6.2% = $4,650
• Medicare: $75,000 × 1.45% = $1,087.50 (no Additional Medicare Tax, since income is under $200,000)
• Total annual tax: $13,552, an effective rate of about 18.07%
• Per paycheck: $2,884.62 gross minus $521.23 total tax, roughly $2,363.39 net

Change any single input, add a 401(k) contribution, switch to married filing jointly, request extra withholding, and every line below it moves. That's the point of running your own numbers instead of trusting a generic percentage.

Withholding vs. Capital Gains Tax: Two Different Tax Events

It's easy to assume this calculator covers "my taxes," but payroll withholding only ever applies to wages. If you sold stock, crypto, a rental property, or other investments this year, that profit is taxed under separate rules, short-term or long-term capital gains tax, and in most cases nothing is withheld from the sale automatically. The liability shows up as a lump sum at filing, or as a quarterly estimated payment you have to make yourself.

If you have investment sales to account for, run them through the Capital Gains Tax Calculator separately, increasing your W-4 withholding on this page will not cover a capital gains bill, and confusing the two is one of the more common reasons people are surprised at tax time despite "having withholding handled."

Withholding Edge Cases Worth Knowing About

My bonus got taxed at a much higher rate than my regular paycheck. Is that a mistake?
No. Supplemental wages like bonuses are typically withheld at a flat 22% federal rate (37% above $1 million in a year), separate from the bracket-based math this calculator uses for regular pay. If your marginal rate is below 22%, the difference comes back at filing.

I have two jobs and both employers withhold as if it's my only income. Will I owe money?
Probably. Each employer withholds based only on what it pays you, so combined household income can land in a higher bracket than either payroll system assumed. Use the IRS Multiple Jobs Worksheet or add extra withholding on Line 4(c) of the higher-paying job's W-4.

I updated my W-4 in October. Does that fix my withholding for the whole year?
No, a new W-4 only changes withholding on paychecks issued afterward. It cannot retroactively correct tax already withheld from earlier paychecks, so a late-year fix only closes part of a gap that built up over nine or ten months.

Why does this calculator use "allowances" when the current W-4 doesn't have them anymore?
The 2020 W-4 redesign replaced allowances with dollar entries for dependents and deductions, but the math is equivalent. Each allowance here approximates roughly $4,300 of income exclusion, which keeps this calculator simple without requiring you to fill out a full W-4 to test a scenario.