How Our Paycheck Calculator Works

Updated for 2026 tax year · figures checked on November 4, 2026

Wageview estimates what your employer withholds from one paycheck, the way a payroll system does. It uses the withholding methods the IRS and each state publish for employers, not the tax return you file in spring. This page explains each step, where every number comes from, how we test the results and what the calculator leaves out.

The calculation, step by step

Each estimate runs the same steps in the same order. Pay is assumed to be the same every pay period.

Gross pay for the period. A salary is divided by the number of paychecks in the year (52 weekly, 26 bi-weekly, 24 semi-monthly or 12 monthly). Hourly pay is your rate times your weekly hours times 52 weeks, divided the same way. Overtime adds overtime hours times your hourly rate times the multiplier you choose, such as 1.5 for time-and-a-half. For a salary, the hourly rate is the salary divided by 52 weeks of your regular hours.
Pre-tax deductions. These come out before some taxes are figured. A traditional 401(k) lowers the wages used for federal income tax but not for Social Security or Medicare. Health insurance premiums under a Section 125 plan and HSA contributions through payroll lower all three. Each state file lists which deductions also lower state taxable wages, because states differ.
Federal income tax withholding. We follow Worksheet 1A in IRS Publication 15-T, the percentage method for automated payroll systems, for a Form W-4 from 2020 or later. Your taxable pay is annualized, adjusted for the W-4 steps you fill in, run through the annual table for your filing status (with a separate table when the Step 2 box is checked), reduced by your Step 3 credits, divided back into paychecks, and increased by any extra withholding from Step 4(c). It never goes below zero.
Social Security. 6.2% of your Social Security wages until your pay for the year reaches the wage base of $184,500. Enter the wages you have already been paid this year to see a paycheck after you reach it.
Medicare. 1.45% of all Medicare wages, plus the 0.9% Additional Medicare Tax that employers withhold on pay above $200,000 in a year, whatever your filing status.
State income tax withholding. Each state's own employer method, applied to that state's taxable wages. States with no tax on wages show zero.
Local income tax. City, county or school district tax where it applies. Local taxes are being added state by state.
State payroll programs. Employee contributions to programs such as paid family and medical leave, disability insurance or long-term care, at the rate and wage cap each program publishes.
After-tax deductions. Roth 401(k) contributions and anything else taken from pay after tax.
Net pay. Gross pay minus everything above. If deductions would push take-home pay below zero, the calculator reduces after-tax deductions first, then 401(k) contributions, and tells you it did.

Yearly figures add up every paycheck in the year one by one, so the Social Security wage base and the Additional Medicare threshold take effect on the paycheck where you would reach them. For most people this equals one paycheck times the number of paychecks.

Rounding

All money is handled in whole cents. Publication 15-T allows employers to round wages and withholding to whole dollars but does not require it, so we don't: each tax is worked out exactly and rounded once, to the nearest cent, at the end. Your employer may round to the dollar, so your paycheck can differ from ours by a few cents or, when an employer rounds, by up to a dollar for each tax.

Where the numbers come from

Every rate, bracket, limit and threshold is copied from an official source and stored with that source's address and the date we checked it. The build fails if any figure is missing its source. We don't use other paycheck calculators as a source.

Federal sources for 2026

State figures come from each state's department of revenue, labor department and unemployment insurance agency, and from the official pages of state programs such as paid family leave. Every state page lists the exact documents it uses, with links, at the bottom of the page.

How we test the calculator

The tax engine is separate from the website and covered by automated tests that run before every release. A release can't go out if any test fails.

Checked against the IRS's own tables. Publication 15-T also prints wage bracket tables for employers who work out payroll by hand. We extracted all 725 rows of the weekly, bi-weekly, semi-monthly and monthly tables, for every filing status, with and without the Step 2 box. For each row, the engine must produce the printed amount.
Hand-worked examples. Each state has at least six cases worked out by hand, covering low, middle and high pay, every filing status the state uses and more than one pay frequency. Each case lists the table rows it used.
Edge cases. Zero pay, pay one cent either side of every bracket boundary, the Social Security wage base, the Additional Medicare threshold, deductions larger than pay and very high overtime.
Rules that must always hold. Thousands of random inputs check that take-home pay is never negative or above gross pay, no tax is ever negative, and total tax never falls when pay rises.

A state page is published only after its tests pass and the site owner has spot-checked its key figures against the official sources.

When the figures are updated

The IRS usually publishes the next year's withholding tables in December, and the Social Security Administration announces the next wage base in October. Many states publish their tables in December or January. When they do, we copy the year's data, update every changed figure from the new documents, rerun every test and recheck each state before its page shows the new year. Each calculator page shows the tax year it uses and the date its figures were last checked.

What the calculator leaves out

The estimate is only as good as its inputs and assumptions. It doesn't cover:

Forms W-4 from 2019 or earlier, which use withholding allowances.
Nonresident alien employees, who have an extra IRS adjustment.
Pay that changes from one paycheck to the next, such as commissions or uneven hours.
Annual contribution limits for 401(k) plans. The calculator warns when HSA or FSA amounts look too high, but it doesn't stop 401(k) contributions at the yearly limit.
Working in one state and living in another, and reciprocity agreements between states.
State withholding on bonuses paid separately (federal flat-rate withholding is included).
Wage garnishments, union dues and other employer-specific deductions, unless you enter them as after-tax.

Withholding is not the same as the tax you owe. When you file your return, your actual tax may be more or less than what was withheld. For advice about your situation, talk to a tax professional.