Unit converter. Exact factors, live results.
Calculated locally, nothing is sent anywhere.
Common length conversions
Quick reference- 1 m3.28084 ft
- 1 km0.621371 mi
- 1 cm0.393701 in
- 1 mi1.609344 km
- 1 ft0.3048 m
- 1 in2.54 cm
Accurate conversions, fully offline
Every factor here is exact (the inch is defined as 25.4 mm, a mile as 1609.344 m, and so on), and temperatures use the proper offset formulas, not naive multiplication. It all runs in your browser, so it works on a plane with no signal and never sends a thing. Type in either field: the converter is two-way, so entering an output value recalculates the input.
Exact factors behind every result
These are the values the converter calculates with, each written in its category's base unit. US and imperial lengths, weights and areas follow the 1959 international yard and pound agreement, which fixed the yard at 0.9144 m and the pound at 0.45359237 kg. US liquid measures come from the 231 cubic inch gallon, and the UK gallon is defined as 4.54609 L. The cup is the US customary cup of 8 US fluid ounces, not the 240 mL cup on US nutrition labels. Kilometers per hour and knots are the only factors that never end, so they are shown as fractions and rounded to six places. Months and years use fixed lengths of 30 and 365 days.
| Unit | In meters |
|---|---|
| Millimeter (mm) | 0.001 m |
| Centimeter (cm) | 0.01 m |
| Kilometer (km) | 1,000 m |
| Inch (in) | 0.0254 m |
| Foot (ft) | 0.3048 m |
| Yard (yd) | 0.9144 m |
| Mile (mi) | 1,609.344 m |
| Nautical mile (nmi) | 1,852 m |
| Unit | In kilograms |
|---|---|
| Milligram (mg) | 0.000001 kg |
| Gram (g) | 0.001 kg |
| Metric tonne (t) | 1,000 kg |
| Ounce (oz) | 0.028349523125 kg |
| Pound (lb) | 0.45359237 kg |
| Stone (st) | 6.35029318 kg |
| US ton, 2,000 lb | 907.18474 kg |
| Imperial ton, 2,240 lb | 1,016.0469088 kg |
| Unit | Formula |
|---|---|
| Celsius to Fahrenheit | °F = °C × 9/5 + 32 |
| Fahrenheit to Celsius | °C = (°F - 32) × 5/9 |
| Celsius to Kelvin | K = °C + 273.15 |
| Kelvin to Celsius | °C = K - 273.15 |
| Unit | In square meters |
|---|---|
| Square millimeter (mm²) | 0.000001 m² |
| Square centimeter (cm²) | 0.0001 m² |
| Hectare (ha) | 10,000 m² |
| Square kilometer (km²) | 1,000,000 m² |
| Square inch (in²) | 0.00064516 m² |
| Square foot (ft²) | 0.09290304 m² |
| Square yard (yd²) | 0.83612736 m² |
| Acre (ac) | 4,046.8564224 m² |
| Square mile (mi²) | 2,589,988.110336 m² |
| Unit | In liters |
|---|---|
| Milliliter (mL) | 0.001 L |
| Cubic meter (m³) | 1,000 L |
| US teaspoon (tsp) | 0.00492892159375 L |
| US tablespoon (tbsp) | 0.01478676478125 L |
| US fluid ounce (fl oz) | 0.0295735295625 L |
| US cup | 0.2365882365 L |
| US pint (pt) | 0.473176473 L |
| US quart (qt) | 0.946352946 L |
| US gallon (gal) | 3.785411784 L |
| UK gallon | 4.54609 L |
| Unit | In meters per second |
|---|---|
| Kilometer per hour (km/h) | 1,000 ÷ 3,600 ≈ 0.277778 m/s |
| Mile per hour (mph) | 0.44704 m/s |
| Foot per second (ft/s) | 0.3048 m/s |
| Knot (kn) | 1,852 ÷ 3,600 ≈ 0.514444 m/s |
| Unit | In bytes |
|---|---|
| Bit | 0.125 B |
| Kilobyte (KB) | 1,000 B |
| Megabyte (MB) | 1,000,000 B |
| Gigabyte (GB) | 1,000,000,000 B |
| Terabyte (TB) | 1,000,000,000,000 B |
| Kibibyte (KiB) | 1,024 B |
| Mebibyte (MiB) | 1,048,576 B |
| Gibibyte (GiB) | 1,073,741,824 B |
| Tebibyte (TiB) | 1,099,511,627,776 B |
| Unit | In seconds |
|---|---|
| Millisecond (ms) | 0.001 s |
| Minute (min) | 60 s |
| Hour (h) | 3,600 s |
| Day (d) | 86,400 s |
| Week (wk) | 604,800 s |
| Month, 30 days (mo) | 2,592,000 s |
| Year, 365 days (yr) | 31,536,000 s |
How to use the Unit Converter
This converter changes a value from one unit to another across eight categories: length, weight, temperature, area, volume, speed, digital storage and time. It converts through each category's base unit using exact defined factors, and uses offset formulas for temperature. It is for anyone checking a recipe, a spec sheet, a file size or a travel distance.
Step by step
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Pick a category
Press Length, Weight / Mass, Temperature, Area, Volume, Speed, Digital storage or Time. Length is selected when the page opens. Each category loads a sensible starting pair, such as meters to feet or kilograms to pounds.
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Enter a value and its unit
Type a number in the From box and choose its unit from the menu below it. The value starts at 1. Decimals and negative numbers work, which matters for temperatures below zero.
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Choose the target unit
Pick the unit you want under To. The answer appears in the To box and in the green result panel as you type, with no button to press.
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Reverse or swap
Type in the To box to work backwards; the From value recalculates. Or press the round Swap units button between the two sides to flip the units, which also carries the current answer across into From.
Reading the result
- With the defaults the panel reads 1 m equals 3.28084 ft, followed by the same sentence in words. The panel shows up to six decimal places; the To box keeps up to 10 significant digits so you can copy a more precise figure.
- Very small or very large answers, under 0.0001 or at least a thousand trillion, switch to scientific notation such as 1.5e-7.
- Digital storage keeps decimal and binary units apart: 1 GB (1,000,000,000 bytes) is 0.931323 GiB, which is why a drive shows less space in some operating systems.
- The Quick reference card lists common conversions of 1 unit for the category you are in, six for most categories and four for temperature, and the Exact factors tables show every value the converter uses.
Tips and common mistakes
- Temperature uses offsets, not a single factor, so 100 °C is 212 °F and 0 °C is 273.15 K. Doubling a Celsius value does not double its Fahrenheit value.
- The cup here is the US customary cup of 8 US fluid ounces, about 236.6 mL, not the 240 mL cup used on US nutrition labels.
- Month and year use fixed lengths of 30 and 365 days, so long time spans in months or years are approximate.
- Choose Gallon (UK) for imperial recipes and fuel figures. It is about 20% larger than the US gallon.
Privacy and limits
Every conversion is calculated in your browser. Nothing you type is sent anywhere and nothing is saved, so reloading the page resets it to 1 meter in feet. Once the page has loaded it keeps working without a connection.
Eight categories, one converter.
Frequently asked questions.
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Published · Last updated .
