How to Convert Units Online
Metric to imperial, Celsius to Fahrenheit, gigabytes to megabytes — unit conversions are one of those things you need to do often enough that memorizing every ratio is impractical, but not often enough that you remember them all.
Supported unit categories
| Category | Example conversions |
|---|---|
| Length | meters ↔ feet, km ↔ miles, inches ↔ cm |
| Weight | kg ↔ pounds, grams ↔ ounces |
| Temperature | Celsius ↔ Fahrenheit ↔ Kelvin |
| Volume | liters ↔ gallons, ml ↔ fluid ounces |
| Speed | km/h ↔ mph, m/s ↔ knots |
| Area | m² ↔ ft², acres ↔ hectares |
| Digital storage | GB ↔ MB, TB ↔ GB, bits ↔ bytes |
| Time | hours ↔ minutes, days ↔ seconds |
How to convert units
- Select the category — choose length, weight, temperature, or another unit type.
- Pick your units — select the source unit and the target unit from the dropdowns.
- Enter a value — type a number in either field. The conversion is bidirectional and updates in real time.
Common conversions to know
Some conversions come up so often they are worth having a rough sense of:
- 1 mile ≈ 1.6 km — multiply km by 0.62 to get miles
- 1 kg ≈ 2.2 pounds — multiply kg by 2.2 to estimate pounds
- 1 inch = 2.54 cm — this one is exact
- 0°C = 32°F — water freezes at 32°F
- 1 liter ≈ 0.26 US gallons — roughly 4 liters per gallon
- 1 GB = 1024 MB — in computing (1000 MB in the SI definition)
Tips
- Type in either field — the converter works both ways. If you know the target value and want to find the source, just type in the other box.
- Temperature is not a ratio — unlike length or weight, temperature conversions use an offset (adding 32 for Fahrenheit). You cannot simply multiply. Always use the formula or a converter.
- GB vs GiB — in computing, 1 GB can mean 1000 MB (SI) or 1024 MB (binary/GiB). Know which definition your context uses.
- Works on any device — the converter runs in your browser on desktop, tablet, or phone.
Frequently Asked Questions
What is the difference between metric and imperial units?
Metric uses meters, kilograms, liters, and Celsius. Imperial (and US customary) uses feet, pounds, gallons, and Fahrenheit. Most of the world uses metric; the US primarily uses imperial for everyday measurements.
How do you convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32. For example, 25 C = (25 x 9/5) + 32 = 77 F. Going the other way, subtract 32 and multiply by 5/9.
Are the conversions exact?
Most conversions use exact mathematical ratios (1 inch = 25.4 mm exactly). Temperature conversions and a few others use formulas. Results are accurate to about 15 significant digits, which is more than enough for any practical purpose.
Does the converter work offline?
Yes. Once the page loads, all calculations run locally in your browser with no internet connection needed.