Unit Converter for Length, Weight and Temperature
Convert length, weight, and temperature instantly. Free, private, no sign-up.
Result
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How to use the unit converter
- Pick a category: Length, Weight or Temperature.
- Type the value you want to convert. Decimals and negative temperatures are fine.
- Choose the unit to convert from and the unit to convert to.
- Read the result instantly. The line under it shows the exact factor or formula used.
- Use the swap button to reverse the conversion.
Exact conversion factors and formulas
Length and weight conversions multiply by a fixed factor. These factors are exact by definition, so the converter does not round them.
| Unit | Exact value |
|---|---|
| 1 inch | 2.54 cm |
| 1 foot | 30.48 cm (0.3048 m) |
| 1 yard | 0.9144 m |
| 1 mile | 1,609.344 m |
| 1 nautical mile | 1,852 m |
| 1 pound (lb) | 0.45359237 kg |
| 1 ounce (oz) | 28.349523125 g |
| 1 quintal | 100 kg |
| 1 tonne | 1,000 kg |
Temperature formulas
Temperature scales have different zero points, so you cannot just multiply. The converter uses:
- °F = °C × 9/5 + 32
- °C = (°F − 32) × 5/9
- K = °C + 273.15
Worked examples
- Height: 5 ft 7 in = 67 in × 2.54 = 170.18 cm.
- Weight: 60 kg ÷ 0.45359237 = 132.28 lb.
- Temperature: 45 °C (a hot May afternoon in Delhi) × 9/5 + 32 = 113 °F.
- Distance: a 21.1 km half marathon is 21.1 ÷ 1.609344 = 13.11 miles.
Key facts
- 1 inch is exactly 2.54 centimetres.
- 1 pound is exactly 0.45359237 kilograms.
- Water freezes at 0 °C (32 °F, 273.15 K) and boils at 100 °C (212 °F) at sea level.
- −40 is the same temperature in Celsius and Fahrenheit.
Tips and common mistakes
- Do not multiply temperatures. 20 °C is not "twice as hot" as 10 °C, and you must add or subtract the offset (32 or 273.15).
- Feet and inches are not decimals. 5.7 ft is 5 ft 8.4 in, not 5 ft 7 in. Convert 5 ft 7 in as 5 × 12 + 7 = 67 inches.
- Watch the tonne. The metric tonne (1,000 kg) is different from the US short ton (about 907 kg) and the British long ton (about 1,016 kg).
- Kelvin cannot be negative. The converter warns you if a value is below absolute zero.
- For exams, remember the shortcuts 1 inch ≈ 2.5 cm, 1 kg ≈ 2.2 lb and 1 mile ≈ 1.6 km, but use the exact factors when an answer needs precision.
Frequently asked questions
How many centimetres are in an inch?
Exactly 2.54 cm. The inch has been defined as 2.54 cm since the 1959 international yard and pound agreement, so 12 inches (1 foot) is exactly 30.48 cm.
How do I convert pounds to kilograms?
Multiply pounds by 0.45359237, the exact legal definition of the pound. For a quick estimate, divide by 2.2: 150 lb is about 68.04 kg.
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 (1.8) and add 32. For example, 37 °C × 1.8 + 32 = 98.6 °F. To go back, subtract 32 and multiply by 5/9.
How do I convert Celsius to Kelvin?
Add 273.15. Water freezes at 0 °C, which is 273.15 K, and absolute zero is 0 K, which is −273.15 °C. Kelvin is written without a degree sign.
How many metres are in a mile?
A mile is exactly 1,609.344 metres, or about 1.61 km. One kilometre is about 0.621 miles. A nautical mile, used at sea and in aviation, is exactly 1,852 metres.
How many kilograms are in a quintal?
One quintal is 100 kg in India, so 10 quintals make one tonne. Crop prices and minimum support prices are commonly quoted per quintal.