How the amount is worked out
Your employer uses your Form W-4 — filing status, dependents, other income, deductions and any extra withholding you asked for — and IRS Publication 15-T, which sets out the wage bracket and percentage methods for figuring withholding.
Form W-4 for employers: what to collect and how it sets withholding
Why FITW changes between paychecks
- Your gross pay changed, for example overtime or a bonus.
- A pre-tax deduction started or stopped.
- You submitted a new Form W-4.
- The IRS updated its withholding tables for a new year.
If too much or too little is withheld
Withholding is an estimate of your tax for the year; the final amount is settled on your tax return. To change what is withheld from future paychecks, give your employer a new Form W-4.
Questions
Why is there no FITW on my pay stub?
Your W-4 details and pay for the period may mean no federal income tax is due to be withheld. If you think that is wrong, review your W-4 with your employer.
Sources
- IRS — About Form W-4, Employee’s Withholding Certificate
- IRS — Publication 15-T, Federal Income Tax Withholding Methods
- IRS — Publication 15 (Circular E), Employer’s Tax Guide
Official sources checked September 23, 2026. This guide explains how pay documents work; it is not tax or legal advice.
