Free Unit Converter 2026
Convert any unit instantly — length, weight, temperature, volume, speed & more. 10 categories, 100+ units, real-time results. No signup required.
Convert Units Instantly
Comprehensive Unit Conversions
Length & Distance
Millimeter, Centimeter, Meter, Kilometer, Inch, Foot, Yard, Mile, Nautical Mile, Light Year
Weight & Mass
Milligram, Gram, Kilogram, Metric Ton, Ounce, Pound, Stone, US Ton, Imperial Ton
Temperature
Celsius, Fahrenheit, Kelvin with accurate scientific conversion formulas
Volume & Capacity
Milliliter, Liter, Gallon, Quart, Pint, Cup, Fluid Ounce, Cubic Meter, Cubic Foot
Area
Square Millimeter, Square Meter, Hectare, Square Kilometer, Square Inch, Square Foot, Acre, Square Mile
Speed & Velocity
Meter/Second, Kilometer/Hour, Mile/Hour, Knot, Foot/Second, Mach Number
Time
Millisecond, Second, Minute, Hour, Day, Week, Month, Year, Decade, Century
Pressure
Pascal, Bar, PSI, Atmosphere, Torr, mmHg, inHg, Kilopascal, Megapascal
Energy & Power
Joule, Kilojoule, Calorie, Kilocalorie, Watt-hour, Kilowatt-hour, BTU, Electronvolt
Data Storage
Bit, Byte, Kilobyte, Megabyte, Gigabyte, Terabyte, Petabyte, Exabyte
The Most Comprehensive
Free Unit Converter Online
200+ units across 10 categories — convert anything, instantly, right in your browser. No login, no fees, no limits.
See conversions the moment you type — zero button clicks needed.
Industry-standard formulas accurate to 6 decimal places.
Length, weight, temp, volume, area, speed, time, pressure, energy & data.
Recent conversions saved locally so you never lose your work.
Fully responsive — phone, tablet, or desktop, always pixel-perfect.
Everything runs in your browser — no data ever leaves your device.
How to Use in 4 Easy Steps
Choose from Length, Weight, Temperature, Volume, Area, Speed, Time, Pressure, Energy, or Data.
Type any number into the "From" field. Decimals and negative numbers are fully supported.
Choose the source unit and the target unit from the dropdowns.
The answer appears immediately — plus the full formula so you understand the math.
Popular Conversions at a Glance
| Category | Common Examples |
|---|---|
| Length | 1 m = 3.281 ft · 1 km = 0.621 mi · 1 in = 2.54 cm |
| Weight | 1 kg = 2.205 lbs · 1 g = 0.035 oz · 1 lb = 0.454 kg |
| Temp | 0°C = 32°F · 100°C = 212°F · 0°C = 273.15 K |
| Volume | 1 L = 0.264 gal · 1 gal = 3.785 L · 1 cup = 236.6 ml |
| Speed | 100 km/h = 62.14 mph · 1 m/s = 2.237 mph |
| Data | 1 GB = 1024 MB · 1 TB = 1024 GB · 1 KB = 1024 B |
Who Uses This Tool
- Engineering — specs, tolerances & technical docs
- Science — lab measurements & experimental data
- Cooking — metric ↔ imperial recipe conversions
- Travel — distances, temperatures & currency weights
- Education — maths & physics homework helper
- Fitness — weight, distance & calorie tracking
- Construction — materials, areas & dimensions
- Technology — data storage & transfer rates
Accuracy You Can Trust
We use ISO & NIST standard conversion factors. Temperature, mass and data formulas are verified against international standards and updated regularly.
Your Privacy, Guaranteed
Every calculation happens entirely on your device. We never collect, store, or transmit your conversion data — ever.
Always Free, No Limits
No account, no subscription, no ads blocking your results. Unlimited conversions, completely free — forever.
Frequently Asked Questions
Our unit converter uses precise conversion factors and formulas recommended by international standards organizations. All conversions are accurate to at least 6 decimal places, suitable for scientific, engineering, and everyday use.
No! Our unit converter is completely free and requires no registration. Simply visit the page and start converting units immediately. Your conversion history is stored locally on your device.
Yes! Our converter is fully responsive and works perfectly on all devices including smartphones, tablets, and desktop computers. The interface automatically adjusts to provide the best experience on your screen size.
Mass is the amount of matter in an object (measured in kg, g, lb), while weight is the force of gravity on that mass. In everyday usage, they're often used interchangeably. Our converter handles both metric (kg, g) and imperial (lb, oz) mass units.
Select "Temperature" category, enter your Celsius value, choose "Celsius" as the from unit and "Fahrenheit" as the to unit. The formula is: °F = (°C × 9/5) + 32. For example, 0°C = 32°F and 100°C = 212°F.
1 meter equals 3.28084 feet. To convert meters to feet, select "Length" category, enter your meter value, and choose "Meter" to "Foot" conversion. The result appears instantly.
1 kilogram equals 2.20462 pounds. Select "Weight" category, enter your kg value, choose "Kilogram" as from unit and "Pound" as to unit. For example, 10kg = 22.05lbs.
1 US gallon equals 3.78541 liters. For conversion, select "Volume" category and convert between "Gallon" and "Liter". The converter handles both US and Imperial gallons.
No limits! You can perform unlimited conversions completely free. Whether you need one conversion or thousands, our tool is always available at no cost.
Yes! The converter automatically saves your recent conversions in the history section below the converter. This history is stored locally on your device and you can clear it anytime using the "Clear History" button.
Once the page is loaded, the converter works entirely in your browser and doesn't need an internet connection for calculations. However, you need internet to initially load the page. For offline use, you can bookmark the page after loading it once.
See Free Online Unit Converter in action
Free Online Unit Converter
Convert between units instantly: length, weight, temperature, volume, area, speed, time, pressure, energy and data. Type a value, pick your units and see the result update in real time. It is handy for cooking, travel, school, engineering and everyday questions.
Metric and imperial units sit side by side, so you can go from kilometres to miles, kilograms to pounds, or Celsius to Fahrenheit without doing the maths yourself.
100+ units in 10 categories
From millimetres to miles, grams to tons and bits to terabytes.
Instant results
The answer updates as you type, with no button to press.
Metric and imperial
Switch between systems with one selection.
Accurate
Uses standard conversion factors for reliable results.
How to use it
- Choose a category such as length or weight.
- Enter the value you want to convert.
- Select the from and to units.
- Read the converted value instantly.
Frequently asked questions
How do I convert kilometres to miles?
Multiply kilometres by 0.621371. For example, 10 km is about 6.21 miles.
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32. For example, 20 C is 68 F.
Is the unit converter free?
Yes. It is free to use with no signup.
How accurate are the conversions?
They use standard, internationally accepted conversion factors.