How accurate is this calculator?
Every time the site is built, we run our formulas against the examples the IRS and state tax agencies publish in their own withholding guides. 9 of 12 match to the cent; the rest are within a few cents.
| Official source | Example | Official result | Our result | Difference |
|---|---|---|---|---|
| IRS Pub. 15-T (2026), wage bracket table | Biweekly $2,005–$2,025, single | $158.00 | $158.00 | exact |
| IRS Pub. 15-T (2026), wage bracket table | Biweekly $2,005–$2,025, married filing jointly | $78.00 | $78.00 | exact |
| IRS Pub. 15-T (2026), wage bracket table | Biweekly $2,005–$2,025, head of household | $117.00 | $117.00 | exact |
| IRS Pub. 15-T (2026), wage bracket table | Biweekly $2,005–$2,025, single, Step 2 box checked | $273.00 | $273.00 | exact |
| IRS Pub. 15-T (2026), wage bracket table | Monthly $5,025–$5,065, single | $424.00 | $424.00 | exact |
| California EDD Method B (2026), Example E | Semi-monthly $2,400, married, 4 allowances | $4.13 | $4.13 | exact |
| California EDD Method B (2026), Example F | Monthly $4,750, married, 4 allowances | $7.17 | $7.17 | exact |
| New York NYS-50-T-NYS (1/26), Method II example 1 | Weekly $400, married, 4 exemptions | $6.69 | $6.68 | −$0.01 |
| New York NYS-50-T-NYS (1/26), Method II example 2 | Semimonthly $5,000, single, 1 exemption | $258.51 | $258.48 | −$0.03 |
| New York NYS-50-T-NYS (1/26), Method II example 3 | Monthly $50,000, single, 3 exemptions | $3,576.63 | $3,576.64 | +$0.01 |
| Virginia Tax withholding formula example | Semi-monthly $2,649, 5 exemptions | $109.50 | $109.50 | exact |
| Georgia DOR employer guide 2026, percentage method example | Biweekly $935, head of household, 2 dependents | $0.00 | $0.00 | exact |
Federal rows are the IRS wage-bracket amounts for the bracket midpoint (the IRS rounds those tables to whole dollars). New York publishes per-pay-period tables; we use its annual schedule, which can differ by a few cents. Figures checked 12 November 2026.
Why a real paycheck can still differ
The formulas are exact, but your employer's payroll system works from your actual W-4 and state form, your benefits, and your year-to-date pay. The most common differences: the W-4 Step 2 box, pre-tax deductions, a bonus paid in the same check, crossing the Social Security wage base, and local taxes. The pay stub checker finds which line is different.