Unit Converter
Convert length, weight, temperature, volume, area, speed and data units in one workspace — instant results, exact standard factors, nothing uploaded.
Common conversions
How to convert units online
Pick a category
Choose one of the seven tabs: length, weight, temperature, volume, area, speed or data storage. Sensible default units are preselected.
Enter a value and choose units
Type the number you want to convert, then pick the source and target units. The swap button flips the direction instantly.
Read the result
The converted value appears as you type, together with the 1-to-1 formula line. Copy it straight from the result box.
Why convert units here
Exact standard factors
1 inch is 2.54 centimeters by definition, and 1 US gallon is exactly 3.785411784 liters. The converter uses the official factors, not rounded shortcuts.
Temperature done properly
Celsius, Fahrenheit and Kelvin are converted with the real affine formulas instead of a ratio table, so 0 °C is exactly 32 °F and −40 °C equals −40 °F.
Seven families, one workspace
Length, weight, temperature, volume, area, speed and data storage share the same interface — switch categories with one click, swap units with the arrow button.
Local and unlimited
Every conversion is computed in your browser. No upload, no sign-up, no daily quota — whether you convert one value or five hundred.
Common unit conversions at a glance
Reference values for the conversions people look up most. Every number is computed with the exact standard factor, and each card links to a dedicated page for that pair.
Centimeters → Inches
| Given | Equals |
|---|---|
| 1 cm | 0.393701 in |
| 5 cm | 1.9685 in |
| 10 cm | 3.93701 in |
| 30 cm | 11.811 in |
| 100 cm | 39.3701 in |
Meters → Feet
| Given | Equals |
|---|---|
| 1 m | 3.28084 ft |
| 2 m | 6.56168 ft |
| 5 m | 16.4042 ft |
| 10 m | 32.8084 ft |
Kilograms → Pounds
| Given | Equals |
|---|---|
| 1 kg | 2.20462 lb |
| 5 kg | 11.0231 lb |
| 20 kg | 44.0925 lb |
| 60 kg | 132.277 lb |
| 80 kg | 176.37 lb |
Ounces → Grams
| Given | Equals |
|---|---|
| 1 oz | 28.3495 g |
| 2 oz | 56.699 g |
| 4 oz | 113.398 g |
| 8 oz | 226.796 g |
Celsius → Fahrenheit
| Given | Equals |
|---|---|
| 0 °C | 32 °F |
| 20 °C | 68 °F |
| 37 °C | 98.6 °F |
| 100 °C | 212 °F |
| 180 °C | 356 °F |
US gallons → Liters
| Given | Equals |
|---|---|
| 1 gal | 3.78541 L |
| 5 gal | 18.9271 L |
| 10 gal | 37.8541 L |
| 55 gal | 208.198 L |
Square meters → Square feet
| Given | Equals |
|---|---|
| 1 m² | 10.7639 ft² |
| 10 m² | 107.639 ft² |
| 50 m² | 538.196 ft² |
| 100 m² | 1076.39 ft² |
Kilometers per hour → Miles per hour
| Given | Equals |
|---|---|
| 10 km/h | 6.21371 mph |
| 30 km/h | 18.6411 mph |
| 60 km/h | 37.2823 mph |
| 100 km/h | 62.1371 mph |
| 120 km/h | 74.5645 mph |
Gigabytes (1000 MB) → Megabytes (1000 KB)
| Given | Equals |
|---|---|
| 1 GB | 1000 MB |
| 2 GB | 2000 MB |
| 8 GB | 8000 MB |
| 16 GB | 16000 MB |
| 500 GB | 500000 MB |
How each unit family works
Seven families, seven different definition systems. Here is what actually sits behind the numbers you see above.
Length
Metric length is anchored on the meter; imperial length is anchored on the inch, defined since 1959 as exactly 25.4 millimeters. That single definition links every metric and imperial length unit, which is why 1 inch is 2.54 cm and 1 mile is 1.609344 km.
Weight
Mass uses the kilogram as its SI base and the pound as the avoirdupois standard, fixed at 0.45359237 kg. A stone is simply 14 pounds (6.35029 kg). Ounces, pounds and stones all measure mass — unlike fluid ounces, which measure volume.
Temperature
Celsius and Fahrenheit are offset scales, not ratio scales, so the correct conversion is °F = °C × 9/5 + 32. Kelvin starts at absolute zero and keeps Celsius-sized degrees, so K = °C + 273.15. Temperature is the one family that cannot be handled by a single multiplier.
Volume
The liter is defined from the cubic decimeter. US customary volume — teaspoon, tablespoon, cup, pint, quart, gallon — descends from the 231-cubic-inch gallon, while UK imperial volume is roughly 20 percent larger. Every volume unit here is US customary and labeled as such.
Area
Area is length squared, so the factors are squared too: 1 m² is 10.7639 ft², not 3.28084. A hectare is 10,000 m² and an acre is 4,046.86 m², which makes an acre about 0.4 hectares.
Speed
Speed combines a length unit with a time unit. 1 km/h is 1000 m per 3600 s, 1 mph is exactly 0.44704 m/s, and a knot is one nautical mile per hour (1852 m / 3600 s ≈ 0.5144 m/s), the standard for aviation and marine navigation.
Data storage
Digital storage has two competing conventions. SI (KB, MB, GB) counts in powers of 1000 and is what drive packaging uses; binary (KiB, MiB, GiB) counts in powers of 1024 and is what most operating systems report. Offering both explains why a "1 TB" drive shows about 931 GiB.
Why the exact factor matters
Plenty of unit converters online multiply by rounded shortcuts. A 2.5 multiplier for centimeters to inches looks harmless until the answer is off by 1.6 percent — on a 300 cm measurement that is almost 5 cm, enough to ruin a furniture fit or a machining cut.
The factors used here come from the definitions themselves: the 1959 international yard and pound agreement fixed 1 inch at 25.4 mm and 1 pound at 0.45359237 kg, and everything else follows by exact arithmetic. Rounding happens once, at the very end, when the result is displayed with six significant digits.
Region matters as much as arithmetic. US and UK gallons differ by about 20 percent, fluid ounces measure volume while ounces measure mass, and kilobytes and kibibytes are two different sizes. Each of those traps is handled explicitly rather than silently guessed.
FAQ
How accurate are the conversions?
The converter uses official standard factors — 1 inch is exactly 2.54 cm, 1 pound is exactly 0.45359237 kg, 1 US gallon is exactly 3.785411784 liters. Results are rounded to six significant digits for display, which is far beyond everyday precision.
What is the difference between KB and KiB?
KB uses the SI convention (1 KB = 1000 bytes) that storage vendors and network speeds use; KiB uses the binary convention (1 KiB = 1024 bytes) that operating systems often report for file sizes. Both families are provided so a "500 GB" drive and a "500 GiB" drive can be compared correctly.
Does the converter work offline?
Once the page has loaded, everything runs locally in your browser. No value is ever uploaded, so it keeps working even if the connection drops.
Are US and UK units distinguished?
Yes. Volume units are US customary (teaspoon, cup, pint, gallon) and labeled as such. UK imperial units differ by roughly 20 percent — a UK gallon is about 4.55 liters while a US gallon is 3.79 — so keep the region in mind when converting recipes.
How do I convert cm to inches by hand?
Divide by 2.54. For a quick estimate, remember that 1 cm is roughly 0.4 in, 10 cm is about 4 in, and 100 cm is 39.37 in. The converter applies the same division exactly, so type a value and you get the full-precision answer instead of the mental estimate.
How many square feet are in a square meter?
1 m² equals 10.7639 ft². Area is length squared, so the linear factor must be squared too: 3.28084² = 10.7639. Multiplying by 3.28084 instead is the single most common area-conversion mistake.
Is a US gallon the same as a UK gallon?
No. A US gallon is exactly 3.785411784 liters; an imperial gallon is 4.54609 liters, about 20 percent larger. This converter uses US customary volume throughout, which matters when you follow American recipes or compare fuel economy figures.
Can the converter handle negative temperatures?
Yes. The affine formula works on negative values directly: −40 °C equals −40 °F, and −10 °C is 14 °F. Physically impossible readings below absolute zero (−273.15 °C) are still computed, so the math never silently stops working.
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