Calculators
Free online calculators that run entirely in your browser: percentage, age, BMI, dates and standard deviation. No sign-up, nothing uploaded, no waiting.
Math
Dates and time
Finance
Health
By country
The arithmetic runs in your browser. Nothing you type is sent anywhere and nothing is stored, so you can use these with real numbers.
Wikipedia — Calculator
Wikipedia — Percentage
Wikipedia — Body mass index
Wikipedia — Standard deviation
Wikipedia — Gregorian calendar