📝 W-4 Withholding Calculator
Enter your salary and current per-paycheck withholding to see whether your W-4 is on target — or setting you up for a refund or a bill.
How W-4 Withholding Works
Your employer does not know your whole tax picture — it only withholds based on the W-4 you filed. Too little and you owe (plus possible penalties); too much and you gave the IRS an interest-free loan. This calculator benchmarks your withholding against your actual 2026 liability.
The Withholding Formula
Correct / paycheck = Progressive Federal Tax ÷ Pay Periods
The 2026 standard deduction is $15,000 single / $30,000 married filing jointly, and federal brackets run 10%–37%. Compare the "correct" per-paycheck figure to your actual withholding: a positive difference means you are over-withholding (refund coming); negative means under-withholding (bill coming).
Worked Example
Single filer, $85,000 salary, $5,000 in 401(k) contributions, paid biweekly (26 periods). Taxable income = $85,000 − $5,000 − $15,000 = $65,000. Progressive tax: 10% on the first $11,925 ($1,192.50) + 12% on $11,926–$48,475 ($4,386) + 22% on $48,476–$65,000 ($3,635.50) = $9,214/year, or $354.38 per paycheck. If your W-4 currently withholds $300, you are under-withholding by about $54 per paycheck — roughly a $1,414 tax bill at filing time.
Official reference: IRS.gov. This is an estimate for planning only — not tax advice. Verify with a CPA or tax professional before filing.
How to Fix Your W-4
Under-withheld? Add an extra dollar amount on W-4 Step 4(c), or reduce pre-tax contributions. Over-withheld? Increase allowances via Step 3 credits or adjust Step 4(b) deductions. Re-run this checkup after raises, marriage, or new dependents.
When and How to Update Your W-4
Revisit your W-4 after every major life event: marriage or divorce, a new baby (worth a $2,000 Child Tax Credit), a second job, or new investment income. The form's Step 4 is the precision toolkit: 4(a) adds other income (freelance, dividends) so withholding covers it; 4(b) claims deductions beyond the standard deduction to reduce withholding; 4(c) adds a flat extra amount per paycheck — the simplest way to fine-tune. Two earners should both check the box in Step 2 or use the multiple-jobs worksheet; otherwise the standard deduction and brackets get double-counted and you under-withhold. Aim to owe or be refunded under $1,000: within that band you avoid estimated-tax penalties via safe harbor and keep your money working all year instead of lending it to the Treasury interest-free.
Frequently Asked Questions (FAQs)
How do I know if my W-4 is correct?
Compare your per-paycheck federal withholding to the "correct" figure from this calculator. Within a few dollars per paycheck is fine. Off by $50+ per paycheck means a four-figure refund or bill at tax time.
Is a big tax refund good?
A refund means you overpaid during the year — an interest-free loan to the IRS. Ideally your refund or balance due is near zero, keeping the money in your paycheck all year.
What triggers an underpayment penalty?
Owing more than $1,000 at filing can trigger penalties unless you paid at least 90% of the current-year tax or 100% of last year's tax (110% for higher incomes) through withholding or estimates.
Should I claim 0 or 1 on my W-4?
The post-2020 W-4 has no allowances — you enter dollar amounts instead. Use Step 3 for dependents/credits and Step 4 for extra income, deductions, or extra withholding per pay period.
When should I update my W-4?
After a raise, job change, marriage/divorce, a new child, or big changes in deductions. The IRS recommends a Paycheck Checkup at least once a year.
Last updated: September 2026
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Last updated: September 2026