W-4 Withholding Optimizer
Adjust your W-4 to avoid a huge tax bill or oversized refund in April.
Free W-4 Withholding Calculator — Avoid Tax Surprises
Tired of either getting a giant refund (interest-free loan to the IRS) or owing a tax bill in April? Our W-4 optimizer uses your year-to-date withholding to predict whether you're under- or over-withholding — and tells you exactly how to adjust your W-4 Step 4(c).
How to use this tool
- 1
Enter your annual salary and filing status
Single or married filing jointly.
- 2
Add dependents under 17
Each one is worth a $2,000 child tax credit.
- 3
Enter YTD withholding and months elapsed
From your most recent paystub.
- 4
Read the recommendation
We tell you whether to add extra withholding, change allowances, or stay the course.
Pro tips
- If you have two earners or multiple jobs, use Step 2 — otherwise you'll seriously under-withhold.
- Big refund? You loaned the government money interest-free. Adjust your W-4 to keep more each paycheck.
- Owed a lot in April? Use Step 4(c) to add a flat dollar amount of extra withholding per paycheck.
Frequently asked questions
What is a W-4?
A form you give your employer telling them how much federal tax to withhold from each paycheck.
Should I claim 0 or 1?
Allowances were eliminated in 2020. Now you use dependents, deductions, and extra withholding fields. This tool tells you which to adjust.
Will the IRS penalize me for under-withholding?
Yes, if you owe over $1,000 at tax time and didn't pay enough during the year. Quarterly estimated taxes or W-4 adjustments avoid this.
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