Instantly convert between units of length, mass, temperature, area, volume, speed, digital storage and time.
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Standard (SI) conversion factors. Instant in-browser calculation, no account. Exact results, with rounding shown.
Each quantity has a base unit. The conversion turns the value into the base unit (multiplying by the source factor) and then into the target unit:
5 km to miles = 5 × 1000 ÷ 1609.344 ≈ 3.107 miles. Temperature is special: 20 °C = 20 × 9/5 + 32 = 68 °F.
Pick the quantity (length, mass, temperature, area, volume, speed, digital storage or time), the source unit and the target unit, then enter the value. The conversion uses standard SI factors.
1 inch = 2.54 cm, 1 foot (ft) = 0.3048 m, 1 yard = 0.9144 m, 1 mile = 1.609 km. Example: 100 m ≈ 328.08 feet; 5 km ≈ 3.11 miles.
1 kg ≈ 2.205 pounds (lb), 1 ounce (oz) ≈ 28.35 g, 1 tonne = 1000 kg. For UK body weight, 1 stone (st) = 6.35029 kg = 14 lb, so 70 kg ≈ 11.02 stone. Example: 70 kg ≈ 154.3 lb; 500 g ≈ 17.64 oz.
The formulas: °F = °C × 9/5 + 32 and K = °C + 273.15. Example: 37 °C = 98.6 °F = 310.15 K; 20 °C = 68 °F.
1 hectare = 10,000 m², 1 acre ≈ 4046.86 m², 1 km² = 1,000,000 m². Example: 2 hectares = 20,000 m² ≈ 4.94 acres.
1 liter = 1000 ml = 0.001 m³, and 1 US gallon ≈ 3.785 liters. In the UK, 1 imperial gallon ≈ 4.546 liters and 1 UK pint ≈ 0.568 liters (a US pint ≈ 0.473 liters). Example: 1 m³ = 1000 liters; 4 UK pints ≈ 2.27 liters.
1 km/h ≈ 0.2778 m/s, 1 mile/hour (mph) ≈ 1.609 km/h, 1 knot ≈ 1.852 km/h. Example: 100 km/h ≈ 62.14 mph ≈ 27.78 m/s.
Using the factor 1024: 1 KB = 1024 bytes, 1 MB = 1024 KB, 1 GB = 1024 MB, 1 TB = 1024 GB. Example: 2 GB = 2048 MB.
A kilobyte (KB) = 1024 bytes, a megabyte (MB) = 1,048,576 bytes, and a gigabyte (GB) = 1,073,741,824 bytes. A 5 MB file is 5,242,880 bytes.
1 minute = 60 seconds, 1 hour = 3600 seconds, 1 day = 86,400 seconds, 1 week = 604,800 seconds. Example: 7200 seconds = 2 hours.
The metric system (meter, kilogram, liter) is used in most of the world; the UK is officially metric, but imperial units (inch, foot, mile, pound, gallon) remain common in daily life — and in the US.
Conversion factors have many decimals; the result is rounded for display. For maximum precision, use the full calculated value.