Unit Converter - Length, Weight, Temperature, Volume, Speed, Data, Time

About the Unit Converter

The Unit Converter is a completely free online tool covering eight categories — length, weight, temperature, area, volume, speed, data and time — with more than 40 units in total, accurate to four decimal places and computed entirely in your browser. Whether you are a student doing homework, an engineer reading drawings, a shopper comparing overseas listings, or just someone who needs a quick conversion, pick a category, enter a value, choose the "from" and "to" units, and you are done.

How conversion works: route through a base unit

Apart from temperature, all seven other categories use the same logic: convert the source unit to the category's base unit, then convert from the base unit to the target unit. For length the base is the millimeter: 1 meter = 1000 mm and 1 foot = 304.8 mm, so 1 meter = 1000 ÷ 304.8 = 3.2808 feet.

Once you see this, you no longer need to memorise every conversion constant — knowing each unit's factor against the base lets you derive any pair. Temperature is the one exception: Celsius, Fahrenheit and Kelvin have different zero points, so they are not in a pure ratio and must be converted with an offset formula (see below).

Conversion tables for all eight categories

The tables below use the same exact factors as the tool, so the numbers match what it actually outputs (to four decimals).

Length (base: millimeter)

Weight (base: milligram)

Area (base: square meter)

Note: The Chinese unit mu (亩, 666.67 m²) is a completely different system from the acre — 1 acre is about 6.07 mu. Do not treat them as interchangeable.

Volume (base: milliliter)

Note: "Gallon" here means the US gallon (3.7854 L). The imperial gallon is about 4.546 L — roughly 20% larger, which matters a lot when reading fuel-economy figures.

Speed (base: m/s)

Data (base: byte, binary 1024)

Note: Operating systems count in binary (1024) while drive makers label capacity in decimal (1000), so a "1 TB" drive usually shows about 931 GB — a difference of convention, not missing capacity.

Time (base: millisecond)

Temperature (offset, not a ratio)

Formulas: °F = °C × 9/5 + 32; °C = (°F − 32) × 5/9; K = °C + 273.15.

Five worked examples

1. Height: 1.75 m = 5.7415 ft — handy for forms that ask for feet.
2. Weight: 150 lb = 68.0388 kg — imperial body weight into metric.
3. Land area: 1 acre = 4,046.86 m² (about 6.07 mu) — useful when reading overseas property listings.
4. Fuel tank: 50 L = 13.2086 US gallons — North American fuel figures are quoted per gallon.
5. Speed: 100 km/h = 62.1371 mph — reading speed limits when driving abroad.

Common conversion mistakes

• Treating temperature as a ratio: 0 °C is not 0 °F. Remove the offset first, then apply the factor — plain multiplication is always wrong.
• Confusing weight with volume: 1 liter of water weighs about 1 kg, but 1 liter of oil does not — density differs, so the two are not equivalent.
• Mixing up mu and acre: the Chinese mu (666.67 m²) and the acre (4,046.86 m²) differ by roughly a factor of six.
• US vs imperial gallon: 3.7854 L against about 4.546 L — about 20% apart, which skews fuel-economy comparisons.
• 1024 vs 1000 for data: the system and the manufacturer use different bases, which is the real reason a drive looks smaller than advertised.
• Wrong category: "how big is this plot" is area, not length. Identify what is being measured before converting.

Unit Converter FAQ

How many feet are in a meter?

1 meter = 3.2808 feet. The tool uses the exact definition 1 foot = 0.3048 meters; conversely 1 foot = 0.3048 meters.

How do I convert Celsius to Fahrenheit?

°F = °C × 9/5 + 32 and °C = (°F − 32) × 5/9, with K = °C + 273.15. Reference points: 0 °C = 32 °F, 37 °C = 98.6 °F, and −40 °C equals −40 °F.

How many square meters are in an acre?

1 acre = 4,046.86 m²; 1 hectare = 10,000 m² = 2.4711 acres. The Chinese mu (亩) is 666.67 m², so 1 acre is about 6.07 mu — different systems, never interchangeable.

How many MB are in a GB?

In binary, 1 GB = 1024 MB and 1 TB = 1024 GB. Drive makers use decimal (1 GB = 1000 MB), so a "1 TB" drive typically shows about 931 GB in your system.

Why can't temperature be converted by simple multiplication?

Length, weight and similar units are pure ratios — one factor is enough. Celsius, Fahrenheit and Kelvin have different zero points (0 °C is 32 °F, not 0 °F), so you must subtract the offset before applying the ratio; multiplying alone gives the wrong answer.

How to read the result

The result is the equivalent of your input value expressed in the target unit, to four decimal places. In engineering, renovation, shopping or study, putting numbers from different sources into one unit is what makes comparison valid — seeing "0.5 m" as "50 cm" makes it far easier to judge whether something fits. The tool removes the mental arithmetic and the lookup tables so you can focus on the actual decision. To split a converted figure into proportions, pair it with the Percentage Calculator; for fuel figures across units, see the Fuel Cost Calculator.