Unit converter that just works
Type a number, pick two units, and Convee shows the answer the instant you stop typing — plus the same value in every other unit of that category. Everything is calculated on your device, so nothing you enter is ever sent anywhere.
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Why people keep Convee open in a tab
Every category, one page
Length, weight, temperature, volume, area, speed, time and digital storage all live behind the same tabs — no hunting for a separate site each time you switch.
Your numbers stay put
The whole calculation happens in JavaScript on your machine. There is no server round-trip, no logging, and no account, so a recipe measurement or a lab value never leaves the tab.
See the full picture
Beyond the single answer you asked for, Convee lists your value in every unit of the category at once — handy when you are not sure which unit you actually need.
How to convert a unit
Choose a category
Tap Length, Weight, Temperature or any of the other tabs. The unit menus update to match what you picked.
Set your units
Enter the amount, pick the unit you have and the unit you want. Use the swap button to flip the direction in one click.
Read the result
The converted figure appears immediately, and the table below shows the same amount across the whole category.
A quick guide to units
Most everyday confusion comes from mixing measurement systems. The metric system (meters, grams, litres, Celsius) is built on powers of ten, which makes conversions within it trivial. The imperial and US customary systems (feet, pounds, gallons, Fahrenheit) grew from older trade and body-based measures, so their steps are irregular — 12 inches in a foot, 16 ounces in a pound, 8 pints in a gallon. A converter simply holds all of those relationships so you don't have to.
Metric vs. imperial, in one line each
A kilometre is about 0.62 of a mile. A kilogram is roughly 2.2 pounds. A litre is a little over a US quart. And to flip Celsius to Fahrenheit in your head, double the number and add about 30 — close enough for a weather forecast, though Convee gives you the exact figure.
Watch out for the "same name, different size" traps
A US gallon (3.785 L) is noticeably smaller than an imperial gallon (4.546 L), and US and imperial pints differ too. A short ton, a long ton and a metric tonne are three separate weights. Convee labels every unit with its system so you always know which one you are working with.
Why storage sizes can look odd
Digital storage uses base-2 steps here: one kilobyte is 1,024 bytes, one megabyte is 1,024 kilobytes, and so on. That is the convention most operating systems use to report file and disk sizes, which is why a "500 GB" drive shows a bit less once formatted.
Frequently asked questions
How accurate are the conversions?
Convee uses the exact internationally defined factors — for example one inch is precisely 0.0254 metres and one pound is 0.45359237 kilograms. Results are rounded only for display, and very large or very small numbers switch to scientific notation so no significant digits are lost.
Do you store or send anything I type?
No. There is no back-end involved. Your input is converted locally in your browser and is never transmitted, saved, or shared. Close the tab and it is gone.
Which categories can I convert?
Length, weight and mass, temperature, volume, area, speed, time, and digital storage. Each category includes both metric and imperial or US units where they apply.
Can I use it without an internet connection?
Yes. Once the page has loaded, the tool keeps working with the connection off, because all the maths runs on your device rather than a server.
Why does a result sometimes show many decimals?
To stay precise. Some conversions produce long or repeating decimals, so Convee keeps several significant figures and drops to scientific notation for extreme values instead of rounding away accuracy.
Is there any catch — a limit or a paywall?
None. Convee is free to use as often as you like, with no account, no daily cap and no watermark on anything.