Convert units and calculate everyday values

Use focused unit, date, time, percentage, ratio, and time-zone calculators directly in your browser.

Length converterConvert millimetres, centimetres, metres, kilometres, inches, feet, yards, miles, and nautical miles.Weight converterConvert milligrams, grams, kilograms, tonnes, ounces, pounds, and stone.Temperature converterConvert temperatures between Celsius, Fahrenheit, and Kelvin with absolute-zero validation.Area converterConvert square units, hectares, acres, and square miles.Volume converterConvert metric volume, US cooking and liquid units, and imperial gallons.Speed converterConvert metres per second, kilometres per hour, miles per hour, knots, and feet per second.Data unit converterConvert bits, bytes, KB through TB, and KiB through TiB with clear decimal and binary definitions.Age calculatorCalculate years, months, days, and total elapsed days from a date of birth to a chosen date.Date difference calculatorCalculate total days plus complete weeks and remaining days between two calendar dates.Time duration calculatorFind hours and minutes between two clock times, including an optional next-day end time.Percentage calculatorFind a share percentage, a percentage of a value, or the percentage change between two values.Aspect ratio calculatorReduce width and height to a ratio, then calculate matching target dimensions.Time-zone overlap calculatorCompare two same-day working windows on a chosen date with daylight-saving offsets applied.

Clear calculations without setup

Choose a focused calculator, enter the known values, and get an immediate result. Calculations run locally and do not require an account.

Frequently asked questions

Are my values uploaded?

No. These calculations run in your browser.

How should I use the results?

Results are suitable for common reference and planning. Check specialist requirements before using a result for safety-critical, legal, medical, or financial decisions.

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