Practical math, for real life.
We build free, well-researched calculators so that anyone — regardless of background — can answer real-world questions in seconds.
What we do
Running the numbers shouldn't require a finance degree or a physics textbook. We translate the calculations that people actually need — mortgages, body-mass index, tax brackets, unit conversions, project estimates — into simple, trustworthy tools that work on any device.
Every calculator is paired with a plain-language explanation, a clear formula, cited sources, and a named author who stands behind the math. If something is wrong, we want to hear about it — and we fix it.
What we believe
-
Accuracy over flash. A pretty calculator that rounds in the wrong direction is worse than no calculator at all.
-
Plain language. Jargon is a tax on readers. We translate formulas into sentences, not the other way around.
-
Real authors, real accountability. Every tool carries a named author and (where relevant) a named reviewer.
-
Free, and privacy-respecting. No paywalls, no logins to get an answer. Your inputs stay in your browser.
How every calculator is built
-
1
Scope We define who the user is, what question they're answering, and what inputs they realistically have.
-
2
Research We source formulas from primary references — standards bodies, peer-reviewed papers, official guidance.
-
3
Build & test Every formula is unit-tested against known inputs. We include edge cases and sanity checks.
-
4
Review A second specialist reviews the math, the UX, and the explanatory text.
-
5
Publish & maintain When rates, laws or standards change, we update the tool and note the change on the page.
Found a mistake? Want a new calculator?
We read every message. Editors typically respond within two business days.