Unit Converter

A unit converter changes a measurement from one unit to another, such as kilometres to miles or Fahrenheit to Celsius. This converter covers length, mass, volume, area, speed, time, temperature and digital storage. It uses the exact international conversion factors, shows the calculation, and checks the result by converting it back.

Try:

How to use the unit converter

  1. Choose the kind of measurement, such as length.
  2. Enter the value and choose the units to convert from and to.
  3. Press Calculate to see the converted value and the factor used.

Formula

new value=value×size of old unitsize of new unit\text{new value} = \text{value} \times \frac{\text{size of old unit}}{\text{size of new unit}}
F=95C+32F = \tfrac{9}{5}C + 32

Worked example: 5 km to miles

  • Measurement: Length
  • Value: 5
  • From: kilometres (km)
  • To: miles (mi)

✓ Answer checked

5 km=3.1068559612… mi5\text{ km} = 3.1068559612\ldots\text{ mi}
Conversion factor
1 km=0.6213711922… mi1\text{ km} = 0.6213711922\ldots\text{ mi}
Reverse
1 mi=1.609344 km1\text{ mi} = 1.609344\text{ km}
Step-by-step working (2 steps)

  1. Convert to metres

    1 km = 1000 metres.

    5×1000=50005 \times 1000 = 5000

  2. Convert to mi

    1 mi = 1609.344 metres, so divide.

    5000÷1609.344=3.1068559612…5000 \div 1609.344 = 3.1068559612\ldots
Formulas used
new=value×size of old unitsize of new unit\text{new} = \text{value} \times \frac{\text{size of old unit}}{\text{size of new unit}}
How this was checked
  • ✓ Converting the answer back gives exactly the original value.

Exact conversion factors (international definitions, e.g. 1 inch = 2.54 cm exactly); results rounded to 10 decimal places.

Frequently asked questions

How many miles is 5 km?

About 3.107 miles, because one mile is exactly 1.609344 km.

How do I convert Fahrenheit to Celsius?

Subtract 32, then multiply by 5/9. For example, 72 °F is (72 − 32) × 5/9 ≈ 22.2 °C.

Are cups and gallons US or UK?

Cups, pints, fluid ounces and gallons are US measures unless marked UK. A UK gallon is about 20% bigger than a US gallon.

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