What Is a Unit Converter?
A Unit Converter translates a measurement from one unit to another, for example kilometers to miles, pounds to kilograms or Celsius to Fahrenheit. People meet different systems every day. Most of the world uses the metric system, while the United States relies on customary units such as feet, pounds and gallons, and the United Kingdom still mixes metric and imperial measures. A reliable converter removes the guesswork when you cook from a foreign recipe, follow a workout plan, ship a parcel or read a technical specification.
This Unit Converter covers eight categories: length, weight and mass, temperature, speed, area, volume, digital data storage and time. Every conversion goes through a common base unit, such as the meter or the kilogram, using exact international definitions. The international foot, for instance, is defined as exactly 0.3048 meters and the avoirdupois pound as exactly 0.45359237 kilograms. Temperature uses its own formulas because scales like Celsius and Fahrenheit have different zero points.
Along with the main result, a full table shows the same value in every other unit of the category, so one entry answers several questions at once. All calculations happen in your browser, which means the tool is fast and keeps working without a connection.
How to Use the Unit Converter
- Select a category such as Length, Weight, Temperature or Data storage.
- Type the number you want to convert into the Value box. Decimals and negative numbers are allowed.
- Choose the unit you are converting From and the unit you want To. Use Swap to reverse them in one click.
- Read the answer in the large result box, which updates the moment you change anything.
- Scroll through the All conversions table to see the same value in every other unit of that category.
- Press Copy Result to copy the full sentence, such as 1 Meter (m) = 3.2808399 Foot (ft).
Key Features of Our Unit Converter
- Eight categories with more than seventy units in total
- Metric, US customary and imperial units side by side
- Exact international conversion factors
- Dedicated formulas for Celsius, Fahrenheit and Kelvin
- Full table showing every unit at once
- Swap button to reverse a conversion instantly
- Both decimal (KB, MB) and binary (KiB, MiB) data units
- Works offline after the page loads, with nothing sent to a server
Benefits of Using an Online Unit Converter
Accurate conversion prevents expensive and sometimes dangerous mistakes. A recipe that calls for 200 grams is not 200 ounces, a package priced per pound is not priced per kilogram, and a speed limit in miles per hour is not kilometers per hour. Using a precise tool avoids the rounding errors that creep in with mental arithmetic.
Seeing every unit at once also teaches useful relationships. You quickly get a feel for how many centimeters make a foot or how many megabytes fit in a gigabyte, which makes future estimates easier.
Your privacy comes first. The Unit Converter runs entirely in your web browser. Nothing you enter is sent to our servers, which keeps your data private and makes results appear instantly. See our Privacy Policy for details.
Common Use Cases for the Unit Converter
- Converting recipe measurements between cups, milliliters, grams and ounces
- Checking international clothing, luggage and shipping weights
- Translating distances for travel, running and cycling
- Reading weather forecasts in Celsius, Fahrenheit or Kelvin
- Comparing car speeds and aircraft speeds in km/h, mph and knots
- Working out room, land and property sizes in square feet, acres or hectares
- Understanding storage and file sizes in KB, MB, GB and GiB
- Homework and engineering calculations in science classes
Tips for Getting the Best Results
- For temperature, remember the quick estimate: double the Celsius value and add 30 for a rough Fahrenheit figure. Use the tool when you need exact numbers.
- Gallons, quarts and pints in this tool are US units. An imperial gallon is about 20 percent larger, so pick the right one for the country you are working with.
- Storage makers advertise using decimal units where 1 GB equals 1,000,000,000 bytes, while many operating systems report binary units. That is why a new drive looks smaller than advertised.
- Mach speed is approximate because the speed of sound changes with temperature and altitude. The value used here is for sea level at about 15 degrees Celsius.
- Very large and very small results switch to scientific notation, such as 1.2e-10, to stay readable.
Unit Converter FAQ
How accurate is this Unit Converter?
It uses exact international definitions, such as 1 inch equals 25.4 millimeters, and standard double-precision arithmetic. Results are shown to up to eight significant digits.
What is the difference between a gallon in the US and the UK?
A US gallon is 3.785 liters, while an imperial gallon, used in the UK, is 4.546 liters. Both are included, labeled clearly as US gallon and Imperial gallon.
Why does my 1 TB drive show less capacity on a computer?
Manufacturers count 1 TB as 1,000,000,000,000 bytes, while some systems display binary units, where 1 TiB is 1,099,511,627,776 bytes. The Unit Converter includes both so you can compare them.
Can I convert negative temperatures?
Yes. Negative Celsius and Fahrenheit values work fine. The converter only rejects values below absolute zero, which cannot exist.
Does it work without internet?
Yes. After the page has loaded, all conversions run locally in your browser and need no connection.
How do I convert Celsius to Fahrenheit by hand?
Multiply the Celsius value by 9, divide by 5 and add 32. To go the other way, subtract 32 from Fahrenheit, multiply by 5 and divide by 9. The Unit Converter applies these formulas for you and also handles Kelvin.