Paycheck Lab is a free collection of US money calculators and plain-English guides. The goal is simple: help you understand the numbers behind everyday financial decisions before you make them.
What you will find here
- Seven calculators: paycheck, mortgage, personal loan, compound interest, home affordability, auto loan and credit card payoff.
- Every calculator shows the math line by line, so you can check the result instead of trusting a black box.
- Guides that explain how to use the numbers, with worked examples.
How the calculators work
All calculations run in your browser. The numbers you type are not sent to our servers. Paycheck estimates use 2026 federal tax rules and state income tax data for all 50 states and the District of Columbia. They are estimates, so your employer's withholding, your lender's terms and your personal situation can produce different results.
How the site is funded
This site may show advertising and may contain affiliate links. If you buy or sign up through an affiliate link, we may earn a commission at no extra cost to you. Ads and affiliate relationships do not change how the calculators work. See our affiliate disclosure.
Contact
Questions, corrections or ideas? Visit our contact page.