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Convert between metric and imperial units of length, weight, and temperature — see every common unit at once.
A unit converter is a tool that translates a measurement from one unit to another — meters to feet, kilograms to pounds, Celsius to Fahrenheit — without you having to remember every conversion factor. This one covers the three categories people reach for most often in everyday life: length, weight, and temperature. It's a side-by-side reference: you enter one value and see it expressed in every common unit of that category at once, which is handy for following a recipe, reading a spec sheet from a different region, checking a weather forecast in unfamiliar units, or doing homework. Metric and imperial (US customary) units are included for length and weight; Celsius, Fahrenheit, and Kelvin are covered for temperature. All math runs in your browser — nothing you type is transmitted or stored.
Use the tabs at the top to switch between length, weight, and temperature. Your inputs are remembered per category, so tabbing back and forth doesn't reset your values.
Type the number you want to convert into the value field. Decimals and negative numbers are supported — handy for sub-zero temperatures or fractional measurements.
Pick the unit your value is currently in from the dropdown. Every other unit in the category is recalculated automatically.
The grid below shows the same value expressed in every other unit — metric and imperial side-by-side for length and weight, and Celsius/Fahrenheit/Kelvin for temperature.
Length & Weight (linear, via a base unit):
value_base = value × factor_from
value_target = value_base ÷ factor_to
Length base = 1 metre. Factors:
1 in = 0.0254 m 1 ft = 0.3048 m
1 yd = 0.9144 m 1 mi = 1609.344 m
Weight base = 1 gram. Factors:
1 oz = 28.349523125 g 1 lb = 453.59237 g
1 st = 6350.29318 g 1 kg = 1000 g
Temperature (non-linear, via Celsius):
°F → °C: C = (F − 32) × 5/9
°C → °F: F = C × 9/5 + 32
K → °C: C = K − 273.15
°C → K: K = C + 273.15Length and weight conversions are linear — every unit has a fixed ratio to a base unit (metre for length, gram for weight), so converting between any two units reduces to 'multiply by the source factor, divide by the target factor'. Temperature is different because the Celsius, Fahrenheit, and Kelvin scales have different zero points as well as different sizes of degree; the tool routes every conversion through Celsius so the chain of formulas stays consistent and avoids the classic 'double-offset' bug where both scales get shifted twice.
Reference: NIST — Unit conversion factors
| Input | Output |
|---|---|
1 metre | 3.28084 feet · 39.3701 inches A standard doorway is about 2 m / 6.6 ft tall — useful for furniture fits. |
100 pounds | 45.3592 kg · 7.14286 stone Imperial-to-metric weight: the gym plate on a bar in kg rounds to pounds × 0.4536. |
68 °F | 20 °C · 293.15 K Room temperature. °F to °C: subtract 32, then multiply by 5⁄9. |
−40 °F | −40 °C · 233.15 K The only temperature where Celsius and Fahrenheit agree — a useful cross-check. |
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