Unit Converter Pro
Convert a number between units in 14 categories, from everyday length and weight to pressure, energy and fuel economy. You get your chosen conversion and every other unit in the category at the same time. Free preview · Pro required to export. Convert between every unit and copy results free. Downloading the table requires Pro.
Free preview · Pro required to export. Convert between every unit and copy results free. Downloading the table requires Pro.
Why use this tool?
- Recipes, product specs and travel information often arrive in units you do not use. A quick lookup avoids rounding by guesswork.
- Seeing every unit in a category at once is useful when you are not sure which one you need, such as comparing psi, bar and atmospheres.
- Some conversions are easy to get wrong by hand: temperature has an offset, and fuel economy flips direction between miles per gallon and litres per 100 km.
- Data sizes are a common source of confusion between 1,000-based and 1,024-based units, and the converter keeps them separate.
How to use Unit Converter
- Choose a category from the row at the top: Length, Weight, Area, Volume, Speed, Time, Data, Pressure, Energy, Power, Angle, Frequency, Temperature or Fuel economy.
- Type a number into "Amount". Decimals and negative numbers are accepted.
- Pick the unit you are starting from in "From" and the one you want in "To".
- Read the result in the highlighted line, and press "Copy" to copy just the number.
- Press "Swap" to reverse the two units, or use one of the "Common conversions" buttons to jump to a frequent pair. The "All units" panel lists the same amount in every unit of the category.
Features
- 14 categories with 6 to 12 units each
- Metric, US customary and UK imperial units, including separate US and UK gallons and pints
- Temperature in Celsius, Fahrenheit, Kelvin and Rankine, converted with the proper offsets
- Fuel economy in km/L, US mpg, UK mpg and litres per 100 km
- Decimal data units (kilobyte, megabyte) kept apart from binary ones (kibibyte, mebibyte)
- A full list of the amount in every unit of the category, with a button to copy the list
- Large and very small results switch to scientific notation
Supported formats
Takes a number and two units. Results are shown with up to 10 significant digits, and values below 0.0001 or at 1 trillion and above are written in exponent form.
Tips
- Pick the right gallon. A US gallon is 3.785 litres and a UK gallon is 4.546 litres, and both are listed separately.
- For storage, a "500 GB" drive uses gigabytes of 1,000,000,000 bytes, which is about 465 gibibytes. The two are separate units here.
- For fuel economy, a higher mpg is better but a lower litres per 100 km figure is better, so do not compare the two numbers directly.
- The Time category treats a month as 30.4375 days and a year as 365.25 days, so use real dates for anything exact.
Frequently asked questions
How are the conversions calculated?
Most categories convert through one base unit, such as metres for length or joules for energy, using fixed factors. Temperature and fuel economy use their own formulas because an offset or a reciprocal cannot be a simple factor.
Is a calorie here the food Calorie?
No. "Calorie" is 4.184 joules, the small calorie. The food "Calorie" is the kilocalorie, which is listed separately as 4,184 joules.
What is the difference between a kilobyte and a kibibyte?
A kilobyte is 1,000 bytes and a kibibyte is 1,024 bytes. The same split applies to megabyte and mebibyte, gigabyte and gibibyte, and so on.
How accurate is the result?
The factors are the standard exact or widely accepted values, and the display rounds to 10 significant digits. Mach is a fixed 340.29 metres per second, which is a sea-level approximation rather than an exact figure.
Can I convert between different categories, such as weight to volume?
No. Each category converts only within itself, since turning weight into volume needs the density of the material.
Is anything sent to a server?
No. The calculation is done in your browser as you type.
Can I try this Pro tool without an account?
Yes. Convert between every unit and copy results free. Downloading the table requires Pro. Your own input is processed locally in your browser.
Will upgrading keep my work?
Checkout and login open in a separate tab. Keep the workspace open to retain inputs, settings and previews. Files stay in that tab only; keep the originals in case you close or reload it. Export access is checked with the server after payment.
Your files are processed directly in your browser and are not uploaded to HubToolify's servers.