About PocketCalc

PocketCalc is a small, hand-built collection of free calculators that run entirely in your browser. No accounts, no tracking, no upload of the numbers you type in. Just tools that work — fast, on any device, in English and Brazilian Portuguese.

What we make

Each calculator is its own page, its own clean URL, and its own single-purpose tool: a mortgage payment, a percentage, a BMI, a date difference. We build them slowly, one at a time, and only ship one when the math is checked, the page is fast, and the explanation is clear.

How we check the math

Every calculator is backed by a pure function in TypeScript, with a Vitest test suite that covers the formula, edge cases, and the exact numbers shown in the worked examples on the page. If the page says "15% of 80 is 12", a build-time test asserts that the calculator actually produces "12" — not "12.0001" or "12.00".

Where a formula is country-specific (Brazilian income tax, US sales tax, etc.) we cite the source and lock the year. When the rules change, we update the dataset and bump the page's revision date — we don't run the old math against the new year.

How we handle your data

We don't. The values you enter live in the open tab and disappear when you close it. Nothing is sent to a server, nothing is stored, nothing is shared. See our privacy policy for the long version.

Bilingual on purpose

Every calculator ships in English (default) and Brazilian Portuguese, each at its own URL with locale-specific wording, examples and number formatting (e.g. 1.234,56 in pt-BR). The math is shared; the presentation is local. Visitors browsing from Brazil are auto-redirected to the Portuguese version, with a manual language switcher in the header for the override.

Roadmap

The plan is to grow the catalog steadily — finance and health calculators first, then everyday utilities and country-specific tax tools. Quality bar: every page must be useful on its own, not filler. If a calculator can't be made genuinely useful, we don't publish it.

Contact

Spotted a bug, a mistaken formula, or a calculator you'd love to see? Email hello@pocketcalc.app.