How the calculator works
- What your employer withholds: the IRS’s percentage method for automated payroll (Publication 15-T, Worksheet 1A), from your pay and your W-4. With a second job or a working spouse, their job’s withholding is estimated from a basic W-4.
- Your tax for the year: your income, less the standard deduction and any other deductions, taxed at the 2026 rates, less the child tax credit and the credit for other dependents. Refundable credits, including the earned income credit, add to your refund.
- Your new W-4: credits, other income and deductions in the steps the form asks for them, then extra withholding (or more in Step 4(b)) to land on the refund you want.
Examples
For 2026, paid every two weeks, starting from a W-4 with only Step 1 filled in:
| You | When you file | New W-4 | Withheld a paycheck |
|---|---|---|---|
| Single, $75,000 | About even | No change | $295.00 |
| Married, $120,000, two children under 17 | $4,400 refund | Step 3: $4,400 | $216.92 |
| Single, two jobs: $60,000 and $40,000 | $5,530 to pay | Step 4(c): $213 on the $60,000 job | $406.08 |
Two jobs are the most common reason for owing at tax time: each one withholds as if it were your only job, so both use the standard deduction and the lowest tax rates. Checking the Step 2 box on both W-4s fixes it when the pay is about the same.
What a basic W-4 withholds
Single, paid every two weeks, with only Step 1 filled in, in 2026:
| Salary | Withheld a paycheck | Withheld in the year | Tax for the year |
|---|---|---|---|
| $30,000 | $54.62 | $1,420 | $1,420 |
| $50,000 | $146.92 | $3,820 | $3,820 |
| $75,000 | $295.00 | $7,670 | $7,670 |
| $100,000 | $506.54 | $13,170 | $13,170 |
| $150,000 | $951.31 | $24,734 | $24,734 |
| $200,000 | $1,412.85 | $36,734 | $36,734 |
With one job and nothing else to report, the IRS tables are built to withhold about the tax you’ll owe, so the last two columns match.
Two jobs without Step 2
A married couple filing jointly, both working, with neither W-4 changed from Step 1:
| Pay | Withheld | Tax for the year | When you file |
|---|---|---|---|
| $40,000 + $40,000 | $1,560 | $5,240 | $3,680 to pay |
| $60,000 + $40,000 | $3,620 | $7,640 | $4,020 to pay |
| $75,000 + $75,000 | $9,280 | $15,340 | $6,060 to pay |
| $100,000 + $60,000 | $10,480 | $17,540 | $7,060 to pay |
| $150,000 + $100,000 | $22,980 | $37,468 | $14,488 to pay |
Each employer withholds as if its job were the only one, so the shortfall grows with the second income. Checking Step 2 on both W-4s, or adding extra withholding in Step 4(c), fixes it.
What the W-4 doesn’t change
Your W-4 only sets federal income tax. Social Security and Medicare are a fixed share of your pay, and most states with an income tax have their own withholding form.
What this calculator doesn’t include
Self-employment tax, the lower rates on qualified dividends and long-term capital gains, the alternative minimum tax, credits such as those for education and child care, and bonuses, which are often withheld at a flat 22%. W-4s from before 2020, with allowances, work differently.
Learn more
Read our step-by-step guide to how to fill out a W-4, see your whole paycheck with the paycheck calculator, or estimate this year’s refund with the tax refund calculator.