Your W-4 tells your employer how much federal tax to withhold from each paycheck. Get it wrong in one direction and you hand the IRS an interest-free loan all year; get it wrong in the other and you face a surprise bill in April. The modern form has no "allowances" — just five steps, and most people only need two of them.
The five steps
- Step 1 — Personal info: name, SSN, address, and filing status (single, married filing jointly, or head of household). Everyone completes this.
- Step 2 — Multiple jobs or working spouse: the most-skipped and most-costly step. If your household has two incomes, check the box in 2(c) on both W-4s (works well when the jobs pay similarly) — otherwise each employer withholds as if its paycheck were the only one, and you under-withhold.
- Step 3 — Dependents: multiply qualifying children by the Child Tax Credit amount ($2,200 per child in 2026) and other dependents by $500. This directly reduces withholding.
- Step 4 — Adjustments (optional): 4(a) other income like interest or side gigs, 4(b) deductions beyond the standard deduction, 4(c) any extra amount to withhold per paycheck.
- Step 5 — Sign. Unsigned forms are invalid.
When to submit a new W-4
- You got married, divorced, or had a child.
- You or your spouse started or left a job (revisit Step 2 on both forms).
- Last year's refund or balance due was large — either one means miscalibration.
- You started significant side income with no withholding (use 4(a) or 4(c)).
Calibrating it
The goal is withholding that roughly equals your actual tax. Check yourself: estimate your annual liability with the federal income tax calculator, compare against withholding-to-date on your pay stub, and if there's a gap, divide it by remaining paychecks and put that number in 4(c). Then verify what your new take-home looks like with the paycheck calculator.