Everyday calculators

Free Calculator Tools Online

Handle quick math, date math, timing, and random picks in the browser. Start with a percentage or date calculation, then use timers and randomizers for activities and testing.

Percentage Calculator

Calculate percentages, increases, decreases, and ratios.

BMI Calculator

Estimate body mass index from height and weight.

Random Number Generator

Draw one or many random numbers in a custom range.

Prime Checker

Check whether a number is prime with a clear explanation.

Fibonacci Sequence

Generate the first N Fibonacci values in one run.

Days Counter

Count the days between two calendar dates.

Countdown Timer

Run a visible countdown with pause, resume, and reset.

Stopwatch Timer

Measure elapsed time with lap recording.

List Randomizer

Shuffle any list into a random order instantly.

Lucky Draw

Pick a random winner from a list of names or options.