Methodology and sources
Every number on this site comes from a published government formula. This page explains how the calculators work, what they leave out, and where each figure came from.
About PaycheckState
PaycheckState is an independent set of free take-home pay calculators for all 50 states and the District of Columbia, built and maintained by a small team. There is no signup, no paywall, and no data collection beyond anonymous page counts. Our editorial rule is simple: every rate, bracket, deduction, and cap must trace back to a primary source (an IRS publication, a state revenue department formula, or a state labor agency notice), and every page cites those sources. We do not claim CPA or payroll-professional review. We claim that the arithmetic follows the official formulas, and we show the working so you can check it.
Questions or a rate that looks wrong? Write to [email protected].
Federal income tax withholding
Federal withholding follows IRS Publication 15-T, Worksheet 1A (the percentage method for automated payroll systems, for Forms W-4 from 2020 on). The calculator annualizes your pay, adds other income and subtracts deductions from Steps 4(a) and 4(b), subtracts the built-in standard-deduction offset ($8,600, or $12,900 for married filing jointly) unless the Step 2 checkbox is ticked, applies the 2026 STANDARD or Step 2 Checkbox rate schedule for your filing status, divides by pay periods, subtracts the Step 3 dependents credit per period, and adds any Step 4(c) extra withholding. Married filing separately uses the single schedule, as the IRS tables do.
2026 parameters: Rev. Proc. 2025-32 brackets and standard deductions; Publication 15-T (2026) schedules; supplemental rates 22% and 37%. The new W-4 deductions for tips and overtime under the 2025 tax law are not modeled.
Social Security and Medicare
Social Security is 6.2% of wages up to the 2026 wage base of $184,500. Medicare is 1.45% on all wages, plus 0.9% Additional Medicare on wages over $200,000, estimated on an annualized basis (payroll applies it once year-to-date wages cross the threshold, so a mid-year paycheck may differ).
Pre-tax deductions
Traditional 401(k) and 403(b) contributions reduce federal income tax wages but not Social Security or Medicare wages. Section 125 items (health and dental premiums, HSA and FSA contributions through a cafeteria plan) reduce both. State income tax follows the federal treatment unless the state says otherwise; Pennsylvania, for example, taxes 401(k) deferrals, and the calculator handles that. State payroll premiums (paid leave, disability) are assessed on Medicare wages.
State withholding
Each state's employer withholding formula is stored as data and applied by one shared engine: flat rates or graduated schedules; fixed, sliding, stepped, or percent-of-wages standard deductions; per-exemption or fixed exemption amounts; dependent amounts; federal-tax and FICA subtractions; credits off the tax; wage-tiered schedules; low-income floors; employee-elected rates; and payroll premium items with wage caps. Where a state publishes a worked example, our tests reproduce it. Each state page lists what its calculator does not model (for example whole-dollar rounding, rarely used form elections, or optional tables).
We model employer withholding formulas, which are what shows up on a paycheck. Several states deliberately withhold above or below their statutory tax (Ohio, Louisiana, New Jersey, North Carolina, New York City); the calculators follow the withholding tables, and the difference settles on the return.
Local taxes
Where a state has city or county wage taxes, the calculator offers a rate field (Ohio, Michigan, Missouri, Alabama, Pennsylvania, Maryland, Indiana, Kentucky, Delaware) or a resident toggle (New York City). Maryland and Indiana county taxes apply to the state taxable amount; the others apply to Medicare wages. Flat per-period local fees (Pennsylvania's Local Services Tax, Colorado occupational privilege taxes, West Virginia city service fees) are not modeled.
Rounding and display
All math runs in annual dollars. Each line rounds to the cent independently, and take-home pay is derived from the rounded lines, so the displayed breakdown always sums exactly. Some states require per-period rounding to the whole dollar; we show cents and note the rule on the state page.
Update cadence
Federal and state parameters are refreshed every January when the IRS and state agencies publish new tables, and again whenever a state changes its formula mid-year (2026 saw mid-year changes in Ohio, Georgia, Utah, Idaho, Arkansas, and West Virginia). Each state page carries an "Updated for the 2026 tax year" stamp and, where relevant, the date of the latest formula change.
State sources
Primary documents behind each state calculator. The same list appears at the bottom of every state page.