Utilities
Convert units without the mental math
Convert between metric and imperial units across length, weight, volume, temperature, speed, and data.
For the best results: Pick the category first, the unit lists follow it. Data conversions cover both decimal (KB/MB) and binary (KiB/MiB) units, which is why drive sizes never match what the box says.
Computed entirely in your browser. Nothing you enter is uploaded, logged, or stored.
What is Unit Converter?
Unit Converter is a free online utility that converts values between metric and imperial units across length, weight, volume, temperature, speed, and data. The math runs right in the page, so the numbers you enter stay on your device and are never sent anywhere. There is no account step, no limit on how many times you calculate, and it keeps working offline.
- ✦Runs entirely in your browser. Nothing you enter is ever uploaded
- ✦No account, no sign-up, and no data leaves your device
- ✦Works offline once the page has loaded
See it in action
A US listing quotes feet and the spec sheet needs meters, then data sizes and temperatures next.
What you type
Length, 10, meters to feet
What you get
10 meters = 32.81 feet. The same box handles the follow-ups too: switch it to data sizes or temperature and it converts those as well, across nine categories (length, weight, volume, speed, data, temperature, area, pressure and energy).
Tip: Temperature is the category where naive converters fail, because it is an offset scale rather than a ratio, this one handles it properly. Data sizes use the binary steps developers expect.
Use cases
What people use it for
Convert an American recipe from ounces, cups and Fahrenheit into grams and Celsius before you start cooking
Translate an overseas car listing quoted in miles and pounds into the metric figures you think in
Check how many binary gibibytes your computer will report for a drive advertised in decimal gigabytes
Who uses Unit Converter?
Home cooks
turn overseas recipe quantities and oven temperatures into familiar units before the shopping trip
Engineering students
move assignment figures between metric and imperial systems without slipping a decimal place under exam pressure
Online shoppers
make sense of international listings sized in inches, pounds and fluid ounces before committing to buy
How it works
- 1Vary step 1 by tool shape using the existing FORM_TOOL_IDS set in app/(public)/[category]/[tool]/page.tsx. Form tools get "Set the options for what you need." and text tools get "Paste your text into the box." Where a tool's config makes it easy, name its own inputs instead. Steps 2 and 3 stay shared as they are.
- 2Your browser computes the result instantly. Nothing is uploaded anywhere.
- 3Copy the output; the tool keeps working even offline.
Tips for the best results
- Convert once at the end of a calculation rather than mid-way, so rounding errors cannot compound
- Check whether a recipe or listing means US or imperial when gallons, pints or fluid ounces appear
- For storage sizes, confirm whether a specification means decimal GB or binary GiB before comparing drives
- Temperature differences convert by factor alone; only actual temperatures need the offset
- Memorize a few anchors, like 2.54 centimeters to the inch, to sanity-check any converted result
FAQ
Frequently asked questions
Why does my 1 TB drive show up as roughly 931 GB?
Drive manufacturers count in decimal, where a terabyte is a million million bytes. Operating systems have traditionally counted in binary, where the comparable unit is two to the fortieth bytes, properly called a tebibyte. One decimal terabyte equals about 0.909 tebibytes, which many systems still label GB or TB. Nothing is missing from the drive; two different units are wearing the same name.
What is the difference between a kilobyte and a kibibyte?
A kilobyte follows the standard decimal prefix and means exactly 1000 bytes, while a kibibyte is the binary unit of 1024 bytes. The kibi, mebi and gibi prefixes were introduced by standards bodies in 1998 to end decades of ambiguity. In practice, network speeds and storage marketing use decimal units, while memory sizes are inherently binary, so knowing which is which matters.
Why is temperature conversion different from every other conversion?
Length, weight, volume and speed convert by pure multiplication because their scales share a zero. Celsius and Fahrenheit do not: their zeros sit at different physical points, so the conversion needs an offset as well as a factor. That has a subtle consequence: a temperature difference of 10 degrees Celsius converts to 18 Fahrenheit degrees using the factor alone, with no offset applied.
Are the values I convert sent off to a server?
Every conversion is fixed-factor arithmetic carried out by the page itself, so measurements from a confidential engineering drawing or a client specification are computed on your screen and go no further. No account exists, no query is logged, and once loaded the converter is fully functional on a flight with the WiFi off. That also means there is no quota to exhaust.
How precise are the conversion factors used?
Most are exact by international definition rather than measured approximations. The inch has been defined as precisely 25.4 millimeters and the pound as precisely 0.45359237 kilograms since 1959, so converting between them introduces no error at all. Any rounding you see in results is a display choice for readability, not uncertainty in the underlying math.
How do you convert miles to kilometers in your head?
Multiply by 1.6, or use the neat fraction eight fifths: halve the miles, add it back, then add a tenth. Fifty miles becomes eighty kilometers. The exact factor is 1.609344, so the mental shortcut runs slightly low, close enough for road signs but not for anything technical.
Why do UK and US gallons differ?
Britain standardized the imperial gallon at about 4.546 liters in 1824, while the United States kept an older wine gallon of about 3.785 liters. The mismatch cascades into pints and fluid ounces too, which is why a converter must ask which system a recipe or fuel figure comes from.
Is 100 grams the same as 100 milliliters?
Only for water and liquids of similar density, because grams measure mass while milliliters measure volume. For water the two align almost perfectly, which is why the shortcut feels universal. Honey, oil and flour all break it: 100 milliliters of honey weighs roughly 140 grams. Density is the missing link between the two.
Are there any usage limits?
None. Everything is generated locally in your browser, so there is no server cost, no metering, and no daily cap, use it as many times as you like, completely free.
Also useful
Related free tools
More Utilities tools
