About SlickCalcs

SlickCalcs builds free online calculators that show their work.

Every calculator on this site runs instantly in your browser — no sign-up, no downloads, no paywalls. More importantly, every tool explains how it got its answer: the exact formula, a worked example with real numbers, and the authoritative source the formula comes from (the IRS, peer-reviewed research, standards bodies).

Who SlickCalcs is for

We build for regular people making everyday money, health, and math decisions — employees checking a paycheck, families planning a budget, students doing homework. You don't need a finance background to use anything here: every answer is explained in plain language.

How we verify our calculators

• Formulas first. Each tool's math is implemented in tested server-side code, with unit tests covering normal cases and edge cases (like division by zero).
• Sources cited. Every tool page lists its sources. If a formula has known limitations, we say so on the page.
• Reviewed regularly. Each page shows a "Last reviewed" date. Tax brackets, rates and guidelines are re-checked at least annually.

What we are not

Our calculators are planning and educational tools. They are not a substitute for professional tax, financial, legal or medical advice. Always consult a qualified professional before making decisions based on estimates.

Questions, bug reports or calculator requests: see our contact page.