Unit Converter calculator.
Convert length, weight, temperature, area, volume, and speed units..
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Selected units explained
About this calculator
The unit converter helps you quickly change a measurement from one unit into another. Instead of looking up conversion factors by hand, choose a category, enter your value, and select the units you want to compare. The result updates instantly, making the tool useful for everyday calculations, school assignments, recipes, travel planning, fitness tracking, DIY projects, and quick technical estimates.
Unit conversion is based on a simple idea: the measured quantity stays the same, but the unit used to describe it changes. For example, 1 meter and 100 centimeters describe the same length. Most conversions use multiplication or division by a fixed factor. Temperature is different because Celsius, Fahrenheit, and Kelvin scales use different zero points, so those conversions use formulas with an added or subtracted offset.
Supported conversion categories
| Category | Common uses | Example |
|---|---|---|
| Length | Distance, height, room size, travel, construction | Meters to feet, inches to centimeters |
| Weight / mass | Body weight, shipping, recipes, product specs | Kilograms to pounds, ounces to grams |
| Temperature | Weather, cooking, science, HVAC | Celsius to Fahrenheit, Fahrenheit to Celsius |
| Area | Floor plans, land, painting, roofing, landscaping | Square meters to square feet |
| Volume | Liquids, recipes, fuel, containers | Liters to gallons, cups to milliliters |
| Speed | Driving, running pace, cycling, travel | Kilometers per hour to miles per hour |
Unit symbols explained
Each unit in the calculator is shown with its common symbol and full name. This helps avoid confusion between similar abbreviations and makes temperature units clearer. For example, m means meter, while °C means degrees Celsius and °F means degrees Fahrenheit.
| Symbol | Full name | Category | Notes |
|---|---|---|---|
mm | millimeter | Length | One thousandth of a meter |
cm | centimeter | Length | One hundredth of a meter |
m | meter | Length | SI base unit of length |
km | kilometer | Length | 1,000 meters |
in | inch | Length | Imperial / US customary length unit |
ft | foot | Length | 12 inches |
yd | yard | Length | 3 feet |
mi | mile | Length | 5,280 feet |
mg | milligram | Weight / mass | One thousandth of a gram |
g | gram | Weight / mass | Common metric mass unit |
kg | kilogram | Weight / mass | 1,000 grams |
oz | ounce | Weight / mass | Imperial / US customary mass unit |
lb | pound | Weight / mass | 16 ounces |
°C | degrees Celsius | Temperature | Water freezes at 0°C and boils at 100°C at standard pressure |
°F | degrees Fahrenheit | Temperature | Common in the United States for weather and cooking |
K | kelvin | Temperature | Absolute temperature scale; no degree symbol is used |
m² | square meter | Area | Area of a square one meter on each side |
ft² | square foot | Area | Area of a square one foot on each side |
L | liter | Volume | Common metric volume unit |
mL | milliliter | Volume | One thousandth of a liter |
gal | US gallon | Volume | US customary liquid volume unit |
km/h | kilometers per hour | Speed | Metric speed unit |
mph | miles per hour | Speed | Imperial / US customary speed unit |
m/s | meters per second | Speed | SI-derived speed unit |
Common formulas
Many conversions can be written as:
Converted value = Original value × conversion factor
| Conversion | Formula | Example |
|---|---|---|
| Centimeters to inches | cm ÷ 2.54 | 180 cm ÷ 2.54 = 70.87 in |
| Inches to centimeters | in × 2.54 | 12 in × 2.54 = 30.48 cm |
| Kilograms to pounds | kg × 2.20462 | 75 kg × 2.20462 = 165.35 lb |
| Pounds to kilograms | lb ÷ 2.20462 | 180 lb ÷ 2.20462 = 81.65 kg |
| Celsius to Fahrenheit | (°C × 9/5) + 32 | 20°C = 68°F |
| Fahrenheit to Celsius | (°F - 32) × 5/9 | 68°F = 20°C |
| Kilometers per hour to miles per hour | km/h × 0.621371 | 100 km/h = 62.14 mph |
Worked examples
Example 1: Convert 5 kilometers to miles.
Use the factor 1 km = 0.621371 miles. So 5 × 0.621371 = 3.106855 miles. Rounded for everyday use, 5 km is about 3.11 miles.
Example 2: Convert 72°F to Celsius.
Use (°F - 32) × 5/9. So (72 - 32) × 5/9 = 22.22°C. That means 72°F is about 22.2°C.
Example 3: Convert 2 square meters to square feet.
Because area is two-dimensional, the factor is squared. 1 m² = 10.7639 ft², so 2 m² = 21.53 ft².
Tips for accurate conversions
Make sure the category matches the measurement you want to convert. For example, meters and feet are length units, while square meters and square feet are area units. Do not mix weight and volume unless you know the density of the material. Also check whether a measurement uses US customary or imperial units, because some names, such as gallon, can refer to different amounts depending on the system.
FAQ
How does the unit converter work?
Choose a category, enter a value, then select the unit to convert from and the unit to convert to. The calculator applies the correct conversion factor instantly. Temperature conversions use their own formulas because they include an offset, not only a multiplier.
Which unit categories can I convert?
This converter supports common everyday categories including length, weight or mass, temperature, area, volume, and speed. It is useful for schoolwork, recipes, travel, fitness, engineering estimates, and quick household measurements.
Why are temperature conversions different from other units?
Most unit conversions multiply or divide by a fixed factor. Temperature conversions also add or subtract an offset. For example, Celsius to Fahrenheit uses (C × 9/5) + 32, while Fahrenheit to Celsius uses (F - 32) × 5/9.
How do I convert metric to imperial units?
Select a metric unit such as meters, kilograms, or liters as the From unit, then choose the matching imperial or US customary unit such as feet, pounds, or gallons as the To unit. The result updates automatically.
Are US and UK gallons the same?
No. A US gallon and an imperial UK gallon are different sizes. Always check which gallon is required when converting fuel, volume, or recipe measurements.
How accurate are the conversions?
The calculator uses standard conversion factors and rounds the displayed result for readability. For high-precision engineering, scientific, legal, or medical work, verify the required number of significant figures and the official unit standard for your use case.
Can I use this unit converter on mobile?
Yes. The converter is responsive and works on phones, tablets, and desktop browsers. Results update in your browser without requiring an account.