PureTools
Unit Converter
11 categories, length, weight, temperature, volume, area, speed, digital storage, energy, pressure, cooking and fuel economy. Live grid showing every unit at once, precision slider, instant copy.
How to use the Unit Converter
- Pick a category, Length, Weight, Temperature, Volume, Area, Speed, Digital, Energy, Pressure, Cooking, or Fuel Economy.
- Type a value and pick the unit you typed in. Every other unit in the category updates instantly in the grid.
- Use the preset chips for one-tap classic conversions like "ft → m", "lb → kg", "°F → °C", "gal → L", "mph → km/h".
- Adjust the precision slider if you need more or fewer decimals (0 to 10). Useful for engineering calculations vs everyday rounding.
- Click Copy result to grab a clean one-liner, or Copy summary to copy the entire grid as plain text.
Why this converter is different
Most online converters force you to pick a target unit, then click Convert. Ours shows every unit simultaneously, type 60 mph, instantly see it equals 96.56 km/h, 88 ft/s and 26.82 m/s. Add to that 11 categories, including the often-missed cooking measures (cup ↔ tbsp ↔ tsp ↔ ml, life-saver for translating US recipes to metric) and fuel economy (MPG ↔ L/100km, with the right inverse formula, not a wrong linear approximation). For seconds, minutes, dates and durations, use the dedicated Time Converter.
Categories & key units
- Length, m, km, cm, mm, μm, nm, in, ft, yd, mi, nautical miles
- Weight, kg, g, mg, t, lb, oz, st, ct (carats)
- Temperature, Celsius, Fahrenheit, Kelvin, Rankine
- Volume, L, mL, m³, gal (US/UK), qt, pt, cup, fl oz
- Area, m², km², hectares, cm², ft², acres, mi²
- Speed, m/s, km/h, mph, knots, ft/s
- Digital storage, bytes, KB, MB, GB, TB, PB (binary, 1024-based)
- Energy, joules, calories, kcal, kWh, BTU, eV
- Pressure, Pa, kPa, bar, psi, atm, torr
- Cooking, cup, tbsp, tsp, ml, fl oz, oz (mass), g, for recipe translation
- Fuel economy, MPG (US/UK), L/100km, km/L
Common conversions to remember
- 1 inch = 2.54 cm exactly
- 1 mile = 1.609344 km exactly
- 1 lb = 0.45359237 kg exactly
- 0°C = 32°F = 273.15 K
- 1 gallon (US) = 3.785 L · 1 gallon (UK) = 4.546 L
- 1 cup (US) = 240 mL = 16 tbsp = 48 tsp
- 30 MPG (US) ≈ 7.84 L/100km
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply Celsius by 9/5 and add 32. Formula: °F = (°C × 9/5) + 32. For example, 20°C × 1.8 + 32 = 68°F. Body temperature 37°C equals 98.6°F. Pick Temperature in the category dropdown, every other scale (Kelvin, Rankine) updates simultaneously in the live grid. Choose Temperature, enter the Celsius value, and read the Fahrenheit result immediately; the reverse Fahrenheit-to-Celsius conversion updates in the same panel.
How does the live grid mode work?
Most converters force you to pick a target unit, then convert one value at a time. The live grid removes that step: enter your value once, and every unit in the active category updates instantly. The card highlighted in colour represents the unit you typed in. This is faster when you need to compare or scan multiple units, like seeing 60 mph in km/h, ft/s and m/s simultaneously.
Why does Kelvin not allow negative values?
Kelvin is an absolute temperature scale where 0 K is absolute zero (−273.15°C), the coldest temperature physically possible. The same applies to Rankine (0 R = absolute zero). The converter shows a warning if you enter a value below absolute zero, since it would be unphysical. Celsius and Fahrenheit do allow negative values down to absolute zero.
How is fuel economy converted between MPG and L/100km?
Fuel economy is inversely proportional: doubling MPG halves L/100km, so the conversion is not a simple factor. The exact formula is L/100km = 235.215 / MPG (US) or 282.481 / MPG (UK). The tool uses the US gallon by default, which is the most common worldwide. UK gallons are slightly larger (4.546 L vs 3.785 L), so a UK car rated 40 MPG actually uses 7.06 L/100km, not 5.88.
Are digital storage units in this tool binary or decimal?
The tool uses the binary convention by default: 1 KB = 1024 bytes, 1 MB = 1024 KB, etc. This matches what operating systems like Windows display when reporting file sizes and memory. Storage manufacturers and network speeds use decimal (1 KB = 1000 bytes, 1 MB = 1,000,000 bytes), which is why a 1 TB hard drive shows up as ~931 GB in your OS.
Are my conversions saved or sent anywhere?
Calculations run entirely in your browser using vanilla JavaScript, nothing is transmitted, logged or stored on any server. Your last category, unit and value are saved only to your local browser storage so the tool remembers your context on the next visit. The page works offline once loaded. For time unit conversions such as seconds to hours or days to weeks, see the Time Converter. Your data is never used to train AI models or improve machine learning systems.
Why do US and UK measurements with the same name give different results?
Several units share a name but differ in size between the US and UK systems, and using the wrong one produces a meaningful error. A US fluid ounce is 29.574 mL while a UK fluid ounce is 28.413 mL. More significantly, a US gallon is 3.785 L while a UK (imperial) gallon is 4.546 L, a difference of about 20 percent. A US pint is 16 US fluid ounces (473 mL) whereas a UK pint is 20 imperial fluid ounces (568 mL). These differences matter for recipes, fuel economy and pharmaceutical dosing. When the category has a US/UK option, always confirm which system your source document uses before converting. The converter defaults to US units throughout to match the most widely used international standard for English-language content.