Instruments, not gimmicks
Every tool below does one job precisely, loads instantly, and works without an account. Pick one to get started.
The everyday calculators — arithmetic, health, geometry, home projects, and games.
A clean, keyboard-friendly calculator for everyday sums — add, subtract, multiply, divide, with memory.
Open → AdvancedTrig, logs, powers, and constants for coursework, engineering, or quick technical checks.
Open → RatiosFind a percentage of a number, work out a percent change, or solve for the missing value.
Open → HealthBody mass index from height and weight, in metric or imperial, with the standard WHO categories.
Open → ConversionLength, weight, volume, temperature, and speed — convert between common units instantly.
Open → LearningA click-to-count soroban-style abacus for practicing place value and basic arithmetic.
Open → GamesTrack a 501 or 301 game for two players, with suggested checkouts as you go.
Open → Home & gardenWork out area, slabs needed, and an estimated material cost for your patio.
Open → JewelryConvert between US/Canada, UK/Australia, diameter, and circumference.
Open → GeometryEnter radius, diameter, circumference, or area — get every other value instantly.
Open →Focused pages for a single unit family — or use the all-in-one hub.
Millimeters through miles — also covers distance.
Open → WeightMilligrams to tonnes, ounces, pounds, and stone.
Open → VolumeMilliliters, liters, US gallons, cups, and fluid ounces.
Open → TemperatureCelsius, Fahrenheit, and Kelvin, instantly.
Open → SpeedKm/h, mph, m/s, and knots.
Open → TimeSeconds through years, including the calendar year.
Open →The specific pairs people search for most, with a reference table on each.