W-4 Withholding Calculator
Check whether your paycheck withholding is on track for 2026 — and see exactly how much to add on W-4 line 4(c) if you are under-withholding.
Withholding Check
What This Calculator Does
It compares two numbers:
- Your estimated tax liability — what you will actually owe for 2026, calculated from your income, deductions, credits, and the 2026 tax brackets.
- Your projected withholding — what your employer will withhold this year, based on the amount currently coming out of each paycheck.
The difference tells you whether you are heading for a refund or a balance due — and how much to add on W-4 line 4(c) if you are short.
How to Adjust Your W-4
Form W-4 has five steps:
- Step 1 — name, address, Social Security number, filing status
- Step 2 — multiple jobs or a working spouse
- Step 3 — dependents and credits (reduces withholding)
- Step 4(a) — other income not from jobs
- Step 4(b) — deductions above the standard amount
- Step 4(c) — extra withholding per paycheck (this is where you fix under-withholding)
To increase withholding, put a dollar amount on line 4(c). To decrease it, claim credits or deductions in Steps 3 and 4(b). Submit the new W-4 to your employer — it is not filed with the IRS.
The Safe Harbor Rules
You generally avoid an underpayment penalty if you pay at least:
- 90% of your current-year tax liability, or
- 100% of your prior-year tax liability (110% if your prior-year AGI was over $150,000)
If your income jumped this year — a raise, a bonus, a side gig — checking your withholding mid-year is worth the ten minutes.
Common Reasons Withholding Goes Wrong
- Two incomes, one W-4. Both spouses using the single rate, or neither checking Step 2, causes systematic under-withholding.
- Side income. Freelance and gig income usually has no withholding at all — see our quarterly estimated tax calculator.
- Life changes. Marriage, a new child, or a new job can throw off the math. Re-check after any major change.
- Bonuses and RSUs. These are often withheld at a flat 22%, which may be too low if you are in a higher bracket.
The Bottom Line
Withholding is not a set-and-forget setting. Check it once a year — and after any major income change — so you are neither lending the government money for free nor facing a surprise bill in April.
Frequently Asked Questions
How do I know if I am withholding enough tax?
Compare your total annual withholding with your estimated tax liability. If withholding is higher, you get a refund; if lower, you owe. A rough target is to withhold at least 90% of this year's tax or 100% of last year's tax (110% if your AGI was over $150,000) to avoid an underpayment penalty.
How do I change my withholding?
Submit a new Form W-4 to your employer. Step 1 covers your personal information and filing status, Step 2 handles multiple jobs, Step 3 lets you claim dependents and credits, and Step 4 lets you add other income, deductions, and — most useful here — extra withholding on line 4(c).
Which line do I use to increase my withholding?
Line 4(c) of Form W-4: "Extra withholding." Enter the additional dollar amount you want withheld from each paycheck. This calculator shows the per-paycheck figure that would bring you to break-even.
Should I aim for a refund or break-even?
Break-even is usually best — a large refund means you over-withheld and gave the government an interest-free loan all year. Aim for withholding close to your actual liability, with a small cushion if you would rather not risk owing.
Why is my actual withholding different from this estimate?
This tool estimates your liability using 2026 brackets and the standard deduction. Your employer withholds using IRS percentage-method tables and the elections on your W-4, which can differ. Treat the result as a planning estimate and compare it against your actual pay stubs.
Last updated: September 2026 · Reviewed by ScholarPay editorial team · General information only — not tax or financial advice.