General Tools — Online calculators thoughtfully built

Temperature Converter

Convert between Celsius, Fahrenheit, and Kelvin in your browser. Free, private, and instant.

Compute age from date of birth in years, months, and days — with optional live clock and detailed totals. Runs entirely in your browser.

Quick percentage of, change, and share calculations. Free, private, and browser-based — no account required.

Body mass index from height and weight with metric or US units and a simple category guide. General guidance only — not medical advice.

Track hours, breaks, and weekly totals with a timecard grid. Import and export spreadsheets — all processed privately on your device.

Convert millimetres through miles — metric and imperial length units. Free private browser converter.

Convert milligrams through tonnes, plus ounces, pounds, and stone. Free private browser converter.

Compare a date and time across multiple cities with daylight-saving-aware zones. Free private browser converter.