Plain Math Tools

About Plain Math Tools

Plain Math Tools is a set of small, free calculators. Each one answers a single everyday question, and gives you the answer the first time you visit.

How the tools work

• One question, answered fast. No sign-up, no pop-ups, no hunting for the result. The answer updates as you type.
• Private by design. Everything is worked out in your browser. The numbers you enter are never sent to us or anyone else. See the Privacy Policy.
• The working is shown. Where it helps, each tool shows how it got the answer, so you can check it.

Where the numbers come from

The take-home pay calculator uses 2026 federal tax brackets and limits published by the IRS, Social Security figures from the Social Security Administration, and state income tax rates checked against each state's published tables and the Tax Foundation's 2026 state tax data. State disability and paid-leave rates come from each state's 2026 announcements. Rates are rechecked every year before the new tax year starts.

Our results are estimates for general information, not tax, legal or financial advice. Your own paycheck can differ because of your W-4, your employer's payroll settings and local taxes.

Found a mistake?

Tax rules change and errors happen. If a number looks wrong, please let us know and we'll check it.