Unit Converter
Convert between 90+ units across 10 categories — length, weight, temperature, volume, area, speed, time, data size, energy, and pressure. Live, accurate, 100% browser-based.
1 m in every unit
🔢 What This Tool Does
A universal unit converter covering 90+ units across 10 categories: length, weight, temperature, volume, area, speed, time, data size, energy, and pressure. Every conversion uses the exact SI-defined factors — 1 inch = 0.0254 meters, 1 pound = 0.45359237 kilograms — so results are accurate to machine precision.
Type a number, pick the units you need, and see the result instantly. Below the main converter, an "every unit" grid shows your input converted to every other unit in the category at once — perfect when you're not sure which unit you need or want to see the full picture.
📝 Example
Input
Category: Length
From: 1 meter
To: feet
Output
1 m = 3.28084 ft
Also: 100 cm, 1,000 mm
Also: 39.3701 in, 1.09361 yd
Also: 0.000621 mi
⚡ How to Use
- Pick a category using the tab bar at the top (length, weight, temperature, etc.)
- Type a number in the "From" field — you can use commas (1,234) or plain digits (1234)
- Pick the "from" unit and "to" unit from the dropdowns
- See the result instantly in the "To" box — copy it with the copy icon if needed
- Click the swap button to flip the conversion direction, or click any card in the grid below to change the target unit
📚 Popular Conversions
📏 Length
- 1 meter = 3.28084 feet
- 1 mile = 1.60934 km
- 1 inch = 2.54 cm
- 1 yard = 0.9144 m
⚖️ Weight
- 1 kilogram = 2.20462 lb
- 1 pound = 16 ounces
- 1 stone = 14 pounds
- 1 tonne = 1,000 kg
🌡️ Temperature
- 0 °C = 32 °F
- 100 °C = 212 °F
- °F = °C × 9/5 + 32
- K = °C + 273.15
🥤 Volume
- 1 US gallon = 3.78541 L
- 1 UK gallon = 4.54609 L
- 1 cup (US) = 236.588 mL
- 1 tbsp (US) = 14.7868 mL
💨 Speed
- 1 km/h = 0.621371 mph
- 100 km/h = 62.1371 mph
- 1 knot = 1.852 km/h
- 1 m/s = 3.6 km/h
💾 Data size
- 1 KB = 1,000 bytes
- 1 KiB = 1,024 bytes
- 1 GB = 0.931 GiB
- 1 TB ≈ 931 GiB
🎯 Use Cases
🍳 Cooking & recipes
Convert American recipes using cups, tablespoons and fluid ounces to metric (grams, milliliters) — or the other way around. Both US and UK measures included.
✈️ Travel
"What's the speed limit in miles?" "How hot is 32 °C in Fahrenheit?" Convert metric and imperial units at a glance.
🏗️ DIY & construction
Convert plans between feet/inches and meters/centimeters. Square feet to square meters for flooring, acres to hectares for land.
💻 Tech & storage
Figure out why your "1 TB" drive shows as 931 GB. Convert between decimal KB/MB/GB and binary KiB/MiB/GiB with full precision.
🔒 Privacy
- ✓ All conversions run in your browser using plain JavaScript
- ✓ Your inputs are never sent, stored, or logged anywhere
- ✓ Works offline after the first page load
- ✓ No signup, no ads, no tracking of conversions
❓ Frequently Asked Questions
How accurate is this unit converter?
All conversions use the officially defined factors from the International System of Units (SI). For example, 1 inch is defined as exactly 0.0254 meters, 1 pound as exactly 0.45359237 kilograms, and 1 mile as exactly 1609.344 meters. The math runs in JavaScript with double-precision floats — accurate to about 15 significant figures.
Which categories and units are supported?
Ten categories with 90+ units: Length (km, m, cm, mm, mi, yd, ft, in, nautical mile, light-year, parsec), Weight (tonne, kg, g, mg, lb, oz, stone), Temperature (°C, °F, K), Volume (L, mL, m³, US/UK gallons, quarts, pints, cups, tablespoons, teaspoons), Area (km², m², hectare, acre, sq mi/yd/ft/in), Speed (m/s, km/h, mph, knot, ft/s), Time (ms, s, min, hr, day, week, month, year), Data size (bit, byte, KB/MB/GB/TB/PB decimal and KiB/MiB/GiB/TiB/PiB binary), Energy (J, kJ, cal, kcal, Wh, kWh, BTU, ft·lb, eV), Pressure (Pa, kPa, bar, atm, psi, mmHg).
Why are there two different bytes — KB and KiB?
KB (kilobyte) is 1,000 bytes in the decimal SI system used by storage vendors and networking. KiB (kibibyte) is 1,024 bytes in the binary system used by operating systems and memory. So a "1 TB" hard drive sold as 10^12 bytes shows up as about 931 GiB in Windows or Linux. This tool supports both so you can convert between them.
How do I convert Celsius to Fahrenheit?
The formula is °F = °C × 9/5 + 32. So 20 °C = 68 °F, 100 °C = 212 °F (boiling point of water), and 0 °C = 32 °F (freezing point). You can also convert the other way using °C = (°F − 32) × 5/9. The tool does it automatically — just type the number and pick the units.
Are US and Imperial (UK) gallons the same?
No. A US gallon is 3.785 liters (3,785 mL) while a UK / imperial gallon is 4.546 liters (4,546 mL) — about 20% larger. This matters for recipes, fuel economy (MPG US vs MPG UK), and shipping. The converter lists them separately so you can pick the right one.
Why does the result show 6 decimals then round?
The tool shows up to 6 significant figures by default because most real-world uses need at most that. For very small or very large numbers the output switches to scientific notation (e.g. 1.23e-9). The underlying calculation is full double precision, so there's no accuracy loss in the math itself — only in what you see on screen.
Does the tool save my conversions?
No. Nothing is sent to a server, nothing is logged, nothing is stored. Every calculation runs in your browser with plain JavaScript. Works offline after the first page load.
Can I use this for recipes and cooking?
Yes — the Volume category includes US and UK cups, tablespoons, teaspoons, and fluid ounces, plus metric milliliters and liters. Perfect for converting American recipes to metric measurements or vice versa. Just pick Volume and use the grid at the bottom to see the input in every volume unit at once.