How Federal Withholding Is Calculated
Federal withholding is calculated in 5 steps from the W-4:
- Annualize the paycheck: gross pay minus pre-tax deductions, times paychecks per year.
- Add Step 4(a) other income and subtract Step 4(b) deductions.
- Subtract the standard deduction for the filing status in Step 1(c).
- Apply the 2026 brackets and subtract the Step 3 dependents amount.
- Divide by paychecks per year and add Step 4(c) extra withholding.
Social Security (6.2%) and Medicare (1.45%) are withheld separately and do not depend on the W-4.
Form W-4 Steps Explained
- Step 1(c) filing status: single, married filing jointly, or head of household sets the brackets and the standard deduction ($16,100, $32,200, $24,150 for 2026).
- Step 2 multiple jobs: the checkbox halves the brackets for two-earner households; the calculator assumes the box is not checked.
- Step 3 dependents: $2,200 for each child under 17 and $500 for each other dependent lower withholding dollar for dollar.
- Step 4(a), 4(b), 4(c): other income raises withholding, deductions above the standard deduction lower it, and extra withholding adds a fixed amount per paycheck.
Withholding allowances ended with the 2020 Form W-4. Older W-4 forms with allowances use a separate table in Publication 15-T.
Too Much or Too Little Withholding
Over-withholding produces a refund; under-withholding produces a balance due and possibly an underpayment penalty. The IRS waives the penalty when withholding covers 90% of this year's tax or 100% of last year's tax (110% above $150,000 of AGI).
The Tax Refund Calculator checks the year's total withholding against the tax owed.
Withholding for Married Filing Jointly
Married filing jointly gets the lowest withholding of the three W-4 statuses on the same paycheck, because its standard deduction is twice the single amount and its lower brackets are twice as wide.
| Status, $2,500 biweekly | Per paycheck | Per year | Share of pay |
|---|---|---|---|
| Single | $216.15 | $5,620 | 8.6% |
| Married filing jointly | $132.31 | $3,440 | 5.3% |
| Head of household | $174.92 | $4,548 | 7.0% |
Two working spouses who both choose married filing jointly and change nothing else are often under-withheld: each payroll gives the full joint deduction and the wide brackets to one paycheck. Checking Step 2 on both W-4 forms fixes this when the two jobs pay about the same. For unequal pay, the Multiple Jobs Worksheet or the IRS Tax Withholding Estimator is more precise.
Federal Withholding on Biweekly Paychecks
On biweekly paychecks, federal withholding grows faster than pay. The first $619.23 of each single paycheck matches the standard deduction and has nothing withheld; the pay above it is withheld at 10%, then 12%, then the higher bracket rates.
| Biweekly gross pay | Single | Married filing jointly |
|---|---|---|
| $1,000 | $38.08 | $0 |
| $1,500 | $96.15 | $26.15 |
| $2,000 | $156.15 | $76.15 |
| $2,500 | $216.15 | $132.31 |
| $3,000 | $320.38 | $192.31 |
| $4,000 | $540.38 | $312.31 |
| $5,000 | $766.69 | $432.31 |
No pre-tax deductions and no Step 3 or Step 4 entries. Weekly, semi-monthly and monthly paychecks use the same method with 52, 24 or 12 paychecks a year.
Withholding With Dependents on the W-4
Each dependent listed in Step 3 cuts the year's withholding by the credit amount, spread across every paycheck: $2,200 for each child under 17 and $500 for each other dependent.
A head of household paid $2,500 every two weeks with one child enters $2,200 in Step 3. Withholding falls from $174.92 to $90.31 per paycheck.
A married couple on the same paycheck with 2 children enters $4,400. That is more than the $3,440 of yearly tax on the pay, so withholding drops to $0. Any refundable part of the Child Tax Credit arrives only with the tax return, never through the paycheck.
Pre Tax Deductions and Extra Withholding
Pre-tax deductions shrink the pay that withholding is figured on, while Step 4(c) adds a fixed dollar amount at the end.
- Pre-tax: a $150 401(k) deferral from a $2,500 single biweekly paycheck lowers federal withholding from $216.15 to $198.15.
- Step 4(c): asking for $50 extra raises it from $216.15 to $266.15, or $6,920 over the year.
- Step 4(a): $10,000 of interest or side income with no tax taken out raises the same paycheck to $295.
Step 4(b) works the other way: deductions you expect to claim above the standard deduction lower the annual taxable figure before the brackets apply.
Withholding Allowances and Older W-4 Forms
Withholding allowances are gone from the current W-4. The 2020 redesign replaced them with dollar amounts for dependents, other income and deductions.
Each allowance on a 2019 or earlier form lowered the wages subject to withholding by a set amount. An employee who has not filed a newer form keeps those allowances, and payroll still honors them. Filing a 2020 or later W-4 switches to the step method used on this page.
New hires must use the current form. A worker who gives the employer no W-4 at all is withheld as a single filer with no adjustments.
State and FICA Withholding on the Same Paycheck
Federal income tax is only one of several amounts taken from each paycheck. Social Security (6.2%) and Medicare (1.45%) come out of every check, and most states add their own income tax.
| $2,500 biweekly, single | Federal | FICA | State | Total withheld |
|---|---|---|---|---|
| Texas | $216.15 | $191.25 | $0 | $407.40 |
| Pennsylvania | $216.15 | $191.25 | $76.75 | $484.15 |
| Illinois | $216.15 | $191.25 | $123.75 | $531.15 |
The state column uses each state's flat rate before any state allowances. The FICA Tax Calculator breaks the Social Security and Medicare part down further.
Frequently Asked Questions
How much should I withhold on my W-4?
You should withhold enough to match your yearly tax. Filling Steps 1 to 4 accurately does that; add Step 4(c) extra withholding when you have a second job or untaxed income.
How do I calculate my withholding?
You calculate withholding by annualizing your paycheck, subtracting the standard deduction, applying the brackets, subtracting W-4 credits, and dividing by your paychecks. The calculator runs those steps.
Is the IRS withholding calculator accurate?
Yes. The IRS Tax Withholding Estimator is accurate when every income source and deduction is entered. This calculator follows the same Publication 15-T method for one job.
How much federal tax is withheld from a $2,500 biweekly paycheck?
$216.15 is withheld from a $2,500 biweekly paycheck for a single filer with no W-4 adjustments in 2026. Married filing jointly, it is $132.31; head of household, $174.92.
How do you calculate 10% withholding tax?
You calculate 10% withholding by multiplying the payment by 0.10, so a $3,000 payment has $300 withheld. Ten percent is the default federal rate on nonperiodic pension and IRA payments under Form W-4R.
Can I claim exempt from federal withholding?
You can claim exempt only if you owed no federal income tax last year and expect to owe none this year. Exempt status lasts one calendar year, and a new W-4 is due by February 15 to keep it.
When should I update my W-4?
Update your W-4 after any change in family or income: marriage, divorce, a new child, a second job or a large change in pay. The employer must apply a new form by the first payroll period ending at least 30 days after receiving it.
Should both spouses check Step 2 on the W-4?
Yes, when both spouses work and the two jobs pay about the same. The box must be checked on both forms; with very different pay, the Multiple Jobs Worksheet gives a closer result.