Unit Converter
Free unit converter for length, weight, temperature, volume, speed and data storage. Instant, accurate conversions in your browser.
3.2808
1.0000 Meters = 3.280840 Feet
Only three countries have not adopted the metric system for general use — the United States, Liberia and Myanmar — which means anyone reading a recipe, a spec sheet or a set of travel directions from elsewhere ends up converting units regularly.
This converter covers length, weight, temperature, volume, speed and digital storage, with instant conversion as you type and a swap button to reverse the direction.
How to use the Unit Converter
Pick a category
Length, weight, temperature, volume, speed or data. Each category only offers units that can be meaningfully converted between.
Choose the units to convert from and to
Use the swap button to reverse the direction without retyping.
Type a value
The result updates instantly, with sensible precision for the size of the number.
Copy the result
One click copies the converted value to your clipboard.
Common conversions worth memorising
| From | To | Multiply by | Quick approximation |
|---|---|---|---|
| Inches | Centimetres | 2.54 | ×2.5 |
| Feet | Metres | 0.3048 | ÷3.3 |
| Miles | Kilometres | 1.60934 | ×1.6 |
| Pounds | Kilograms | 0.453592 | ÷2.2 |
| Ounces | Grams | 28.3495 | ×28 |
| US gallons | Litres | 3.78541 | ×3.8 |
| Fluid ounces (US) | Millilitres | 29.5735 | ×30 |
| mph | km/h | 1.60934 | ×1.6 |
Temperature is different
Temperature scales have different zero points, so they cannot be converted by a single multiplication like every other unit here.
°C to °F: (°C × 9/5) + 32. °F to °C: (°F − 32) × 5/9. °C to K: add 273.15.
For mental estimates, double the Celsius figure and add 30 — 20 °C gives about 70 °F, and the real answer is 68 °F. The scales cross at −40°, which is the same temperature in both.
The US gallon is not the imperial gallon
A US gallon is 3.785 litres; an imperial gallon, still used in the UK and Canada for some purposes, is 4.546 litres — about 20% larger. US and imperial fluid ounces, pints and quarts differ too.
This trips up recipes constantly. A US pint is 16 fl oz; an imperial pint is 20. This converter uses US customary units, which is the correct choice for American recipes and specifications.
Why data sizes never match the label
A "1 TB" drive shows as about 931 GB in Windows because two different definitions are in play. Manufacturers use decimal units where 1 TB is 1,000,000,000,000 bytes; operating systems traditionally display binary units where 1 TiB is 1,099,511,627,776 bytes.
The gap grows with size: about 2.4% at kilobyte scale, roughly 9.9% at terabyte scale. Nothing is missing from the drive — it is a units mismatch, not lost capacity.
When conversion errors get expensive
NASA lost the $327 million Mars Climate Orbiter in 1999 because one team supplied thrust data in pound-force seconds while the navigation software expected newton-seconds. The spacecraft entered the atmosphere too low and broke up.
In 1983, Air Canada Flight 143 ran out of fuel at 41,000 feet after a metric-imperial mix-up during refuelling. The crew glided it to a landing at Gimli with no fatalities — but the lesson stands: always state the unit, never just the number.
Frequently asked questions
How many centimetres are in an inch?
Exactly 2.54 — this is a defined value, not a measured approximation, since the international yard and pound agreement of 1959.
How do I convert kilograms to pounds?
Multiply by 2.20462. For mental arithmetic, double and add 10% — 70 kg is about 154 lb, which is exact here.
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32. For a rough estimate, double and add 30: 25 °C gives roughly 80 °F against an exact 77 °F.
Is a US gallon the same as a UK gallon?
No. A US gallon is 3.785 litres and an imperial gallon is 4.546 litres, about 20% larger. Pints and fluid ounces differ too.
Why does my 1 TB drive show 931 GB?
The manufacturer counts 1 TB as a trillion bytes; the operating system displays binary tebibytes of 1,099,511,627,776 bytes. Same capacity, different definitions.
What is the difference between mass and weight?
Mass is the amount of matter and never changes; weight is the force gravity exerts on it. Everyday usage treats kilograms as weight, which is technically imprecise but harmless on Earth.
How accurate are these conversions?
They use exact internationally defined factors and full floating-point precision, rounded only for display. They are accurate for engineering, cooking and scientific use.
Which countries do not use the metric system?
The United States, Liberia and Myanmar are the only countries that have not adopted it for general use, though all three use metric units in science, medicine and much of industry.
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