Unit Converter
Length, weight, temperature, volume, area and speed, both ways, with exact factors and a chart.
Works in your browser. Nothing you type is sent to us.
Type in either box. Takes 12, 2.5, 1,500, 1/2 and 1 1/2; for length, feet and inches such as 5'7" or 5 ft 7 in.
In every unit
| Unit | Value |
|---|
Chart
| From | To |
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Unit Converter at a glance
- Price
- Free
- Data sent to us
- None, it runs in your browser
- Sign-up
- Not needed
- Converts
- Length, weight, temperature, volume, area, speed
- Takes
- 12, 2.5, 1 1/2, 5'7"
- Factors
- Exact definitions, 1 in = 2.54 cm
How to use Unit Converter
- Pick the kindChoose length, weight, temperature, volume, area or speed.
- Choose the unitsSet the unit you have and the unit you want, or press swap to turn them round.
- Type the numberThe answer appears at once, with the amount in every unit and a chart for the pair.
Pick what you are converting, type a number in either box and the other fills in at once, using the exact definitions: an inch is 2.54 cm and a pound 0.45359237 kg. Length answers in inches or feet also come as feet and inches to the nearest 1/16 inch, and pounds as pounds and ounces. Below the answer, the same amount in every unit of its kind and a chart of common values for the pair you chose. US and UK gallons, pints and fluid ounces are listed separately.
How it works
Unit Converter is a web page that does its work on your own device. Everything you type or choose is worked out by your browser and never sent to a server, so nothing is stored and there is nothing to delete. There is no account, no sign-up and no limit on how often you use it.
Straight to one job
CM to Inches · KG to LBS · Celsius to Fahrenheit · Feet to Meters · mL to oz
How the conversions are worked out
Every unit is turned into one base unit for its kind (metres, kilograms, litres, square metres or metres per second) and from there into the unit you want. The factors are the exact legal definitions, not rounded figures: since the international yard and pound agreement of 1959 one inch is exactly 2.54 cm and one pound exactly 0.45359237 kg, a US gallon is exactly 231 cubic inches and a UK gallon exactly 4.54609 litres. Answers are shown to ten significant figures, far more than any tape or scale can measure, and the tables to six or seven.
Handy exact factors
| Conversion | Exact factor | Rough rule |
|---|---|---|
| inches to centimetres | × 2.54 | 4 inches is about 10 cm |
| feet to metres | × 0.3048 | divide by 3.3 |
| miles to kilometres | × 1.609344 | 5 miles is about 8 km |
| pounds to kilograms | × 0.45359237 | halve it and take off a tenth |
| ounces to grams | × 28.349523125 | about 28 g |
| US fluid ounces to millilitres | × 29.5735295625 | about 30 mL |
| US gallons to litres | × 3.785411784 | about 3.8 L |
| square feet to square metres | × 0.09290304 | divide by 10.8 |
| acres to hectares | × 0.40468564224 | about 0.4 ha |
Temperature is different
Celsius and Fahrenheit do not start at the same zero, so you cannot just multiply. To go from Celsius to Fahrenheit, multiply by 9/5 and add 32: 25 °C is 77 °F. To go back, take away 32 and multiply by 5/9: 98.6 °F is 37 °C. Kelvin uses Celsius-sized steps starting from absolute zero, so add 273.15 to a Celsius temperature. −40 is the one point where Celsius and Fahrenheit read the same.
US and UK measures are not the same
A US gallon is 3.785 litres and a UK (imperial) gallon 4.546 litres, so a UK gallon is about a fifth bigger. A US fluid ounce is slightly bigger than a UK one, but a UK pint holds 20 UK fluid ounces against the US pint's 16. Recipes, fuel figures and drink sizes from Britain use the UK measures; pick the right one from the list. A US ton is 2,000 pounds, a UK ton 2,240 pounds and a metric ton (tonne) 1,000 kg.
What it does
- Length, weight, temperature, volume, area and speed
- Type in either box, or swap the units
- Exact factors, ten significant figures
- Feet and inches in and out, to the nearest 1/16 inch
- Pounds and ounces
- The amount in every unit of its kind
- A conversion chart for the pair you chose
- US and UK gallons, pints and fluid ounces
Questions
How many centimeters are in an inch?
Exactly 2.54. Since 1959 the inch has been defined as 2.54 cm, so 10 inches is 25.4 cm and 10 cm is 3.937 inches.
How do I convert kg to lbs?
Multiply by 2.20462: 70 kg is 154.32 lb, or 154 lb 5.2 oz. A pound is exactly 0.45359237 kg.
What is the formula for Celsius to Fahrenheit?
Multiply by 9/5 and add 32. 0 °C is 32 °F, 20 °C is 68 °F, 37 °C is 98.6 °F and 100 °C is 212 °F.
How tall is 5 feet 7 inches in cm?
Choose Length, set feet to centimeters and type 5'7" or 5 ft 7 in: it is 170.18 cm.
How many mL are in a fluid ounce?
A US fluid ounce is 29.5735 mL and a UK fluid ounce 28.4131 mL. A US cup of 8 fluid ounces is 236.6 mL.
Is a US gallon the same as a UK gallon?
No. A US gallon is 3.785 liters and a UK (imperial) gallon 4.546 liters. Both are listed so you can pick the one your recipe or label uses.
Where do the factors come from?
They are the exact definitions published by NIST, the US National Institute of Standards and Technology, in its guide to SI units and Handbook 44: the international inch, pound and gallon definitions.
Is anything sent anywhere?
No. The conversion runs in your browser and nothing you type is sent to us or stored.
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