Converters for units, colours, time, and digital values

Use a direct converter when you know the value you have and the value you need. This collection covers physical measurements, temperature, pressure, storage, timestamps, durations, and colour systems without burying the answer in a general calculator.

Each page opens with the correct units and conversion direction already selected. Reverse-direction tools remain separate where people search for and use them as distinct tasks, while related conversions stay connected for quick follow-up work.

Confirm the source unit before entering the number. A US gallon is not an imperial gallon, and a food Calorie is not the small calorie used in physics. Bytes and bits differ by a factor of eight; storage labels can also use 1000 or 1024 as the unit step. A mathematically correct conversion of the wrong unit is still an unusable answer.

For temperature, converting an absolute reading differs from converting an interval. Celsius to Fahrenheit readings include an offset of 32, but a change of 10 Celsius degrees corresponds to a change of 18 Fahrenheit degrees. Kelvin uses the same step size as Celsius with a different zero. Record whether the input is a reading or a difference before carrying the result into a formula.

For time values, separate elapsed duration from clock time and date. A duration of 25 hours should not wrap to 01:00 merely because a clock uses 24-hour days. Unix timestamps require a time-zone interpretation when displayed as local dates. Keep the original time zone or offset when two systems must reconcile events.

Colour conversions map numeric channels; they do not establish legible contrast on a page. Screen scaling also means CSS pixels are not always individual hardware pixels. Convert with full precision, then round for the destination and inspect the real use case. The reverse converter can help check a calculation, but a rounded value may not return exactly to its starting number.

Record significant figures when the original measurement is approximate. Converting 3.2 meters to a long decimal number of feet does not create additional measurement accuracy. For a physical cut or purchase, follow the tolerance and rounding rule specified by the plan or supplier, then label the final result with its destination unit.