Unit Converter

What is a unit converter?

A unit converter changes a measurement from one unit into another while keeping the underlying quantity the same. Two metres and roughly 6.56 feet describe the exact same distance — they are just written in different units. This tool handles the four conversions people reach for most often: length, weight, temperature and digital storage.

Everything runs locally in your browser. There is no sign-up, no waiting on a server, and no data leaving your device. You type a number, pick your units, and the answer updates as you type.

How to use it

1. Choose a category — Length, Weight, Temperature or Data — using the tabs at the top.
2. Pick your "from" unit in the left dropdown and type the value you want to convert.
3. Pick your "to" unit in the right dropdown. The converted result appears instantly beside it.
4. Use the swap button (the two-arrow icon) to flip the units — handy when you realise you had them the wrong way round.
5. Hit Copy result to put the answer on your clipboard, ready to paste into a document, spreadsheet or message.

Because the result is live, you can leave the units fixed and try different numbers, or keep the number and switch units to compare several at once.

How the conversions work

Most units are linear, which means converting is just multiplication. Internally, every length is expressed in metres, every weight in grams, and every data size in bytes. To convert, the tool turns your input into that base unit and then into the unit you asked for. That keeps the maths exact and avoids rounding errors creeping in from chained conversions.

Temperature is the exception. Celsius, Fahrenheit and Kelvin do not share a common zero point, so you cannot convert them by multiplying a single factor. The tool uses the proper formulas instead:

• Celsius to Fahrenheit: multiply by 9/5 and add 32.
• Fahrenheit to Celsius: subtract 32, then multiply by 5/9.
• Celsius to Kelvin: add 273.15.

So 100 °C becomes 212 °F or 373.15 K, exactly as the physics requires.

Metric vs imperial: a quick orientation

If you switch between systems regularly, a few anchor points are worth memorising:

• 1 inch = 2.54 cm (exactly). This is the foundation most other length conversions are built on.
• 1 foot = 30.48 cm, and there are 12 inches in a foot.
• 1 mile ≈ 1.609 km, useful for reading road signs abroad.
• 1 pound ≈ 453.6 g, and 1 kilogram ≈ 2.205 pounds.
• 1 ounce ≈ 28.35 g.

These are the same constants the converter uses behind the scenes, so the numbers you see here will line up with any textbook.

Data sizes: why 1 KB can mean 1024 bytes

Digital storage has a long-running quirk. In everyday computing, sizes climb in powers of 1024 rather than 1000, because memory is addressed in binary — and if you want to see those binary values directly, the Number Base Converter switches a figure between decimal, binary and hex. That is why a "1 GB" download can look slightly smaller once it lands on your disk — the operating system and the marketing department are sometimes counting differently.

This converter uses the binary convention (1 KB = 1024 B, 1 MB = 1024 KB, and so on), which matches what Windows, macOS and most file managers report. If you are working with a context that uses decimal units (1 KB = 1000 B), keep that difference in mind, because for large files it adds up to a noticeable gap.

Reading the results

The tool formats answers to stay readable rather than dumping a long string of decimals. Trailing zeros are trimmed, so a clean conversion like 2 m to cm shows as 200, not 200.00000000. Very large or very small results fall back to scientific notation so the field never overflows. If you need the full-precision value, the copied text carries whatever the screen shows.

Common mistakes to avoid

• Mixing up "from" and "to". It is easy to set both dropdowns and then read the result backwards. If a number looks ten or a hundred times off, try the swap button first.
• Confusing mass and weight. In everyday use "weight" usually means mass (grams, kilograms, pounds), which is what this tool converts. True scientific weight is a force and is measured differently.
• Assuming temperature scales by a factor. You cannot "double" a temperature by converting units — 20 °C is not 40 °F. The offset in the formula matters.
• Forgetting the binary/decimal split for data. A drive sold as "500 GB" may show as roughly 465 GB once formatted, purely because of the 1000-vs-1024 difference.

Private by design

There is no account, no history and no upload. Each calculation happens the instant you type, on your own machine, and disappears when you close the tab. That makes the converter as suitable for sensitive figures as it is for quickly checking a recipe or a parcel weight.