Unit Converter
Convert between metric and imperial units for length, weight, temperature, volume, area, speed, and time. Enter a value, pick your units, and get results.
How to use
Select a category (length, weight, temperature, etc.), enter a value in the "From" field, and choose the units you want to convert between. The result updates as you type. Use the swap button to quickly reverse the conversion direction.
Supported Units
Length: Millimeters, centimeters, meters, kilometers, inches, feet, yards, miles
Weight: Milligrams, grams, kilograms, ounces, pounds, stone
Temperature: Celsius, Fahrenheit, Kelvin
Volume: Milliliters, liters, gallons, quarts, pints, cups, fluid ounces
Area: Square millimeters through square kilometers, square inches through acres
Speed: m/s, km/h, mph, knots
Time: Milliseconds through weeks
When this tool helps
Whether you are an American reading a European recipe in grams, a traveler converting miles to kilometers, a student working on physics homework, or an engineer switching between metric and imperial specifications, unit conversions come up constantly. This converter handles all common categories in one place, no need for separate tools for temperature, weight, and length. The live results and swap button make it fast to check conversions in both directions, and the clean interface means no ads or clutter getting in the way of a simple conversion.
Examples
Example 1: Cooking with a Foreign Recipe
A home cook finds a French recipe calling for 250g of flour and 180°C oven temperature. Using the weight converter: 250g = 8.82 oz (about 2 cups). Using the temperature converter: 180°C = 356°F, so they set the oven to 350°F. Quick conversions make international recipes accessible.
Example 2: Running a 5K Race
A runner training for a 5K wants to know the distance in miles: 5 km = 3.107 miles. They also convert their pace from 5:30 per km to per mile: 5:30/km × 1.609 = about 8:51 per mile. This helps them set their treadmill correctly since most US treadmills display miles.
Example 3: Shipping Package Weight
An online seller needs to ship a 3.5 kg package internationally. The converter shows 3.5 kg = 7.72 lbs. USPS charges by pounds, so they enter 8 lbs for the shipping label. For dimensions, they convert 30cm × 20cm × 15cm to 11.8" × 7.9" × 5.9" for the customs form.
Things to watch
- •Temperature conversions are not proportional, 0°C is 32°F, not 0°F. Always use the formula rather than guessing.
- •A fluid ounce (volume) and an ounce (weight) are different measurements, do not confuse them in recipes.
- •A US gallon (3.785L) is smaller than an Imperial gallon (4.546L), always check which system your source is using.
- •For quick mental math: 1 inch ≈ 2.5 cm, 1 kg ≈ 2.2 lbs, 1 mile ≈ 1.6 km, and 1 liter ≈ 1 quart.
- •Stone (14 pounds) is commonly used for body weight in the UK, 150 lbs = 10 stone 10 lbs, or about 68 kg.
Common questions
- How do I convert Celsius to Fahrenheit?
- To convert Celsius to Fahrenheit, multiply by 9/5 and add 32: F = (C × 9/5) + 32. For example, 0°C equals 32°F, and 100°C equals 212°F. The reverse conversion is: C = (F - 32) × 5/9.
- How many pounds are in a kilogram?
- One kilogram equals approximately 2.20462 pounds. To convert, multiply kilograms by 2.20462. Conversely, one pound equals approximately 0.453592 kilograms. These tools automate this calculation for you.
- What is the metric system?
- The metric system (or SI system) is an international system of units based on powers of 10, including meters (length), kilograms (weight), and liters (volume). It's used by most countries worldwide except the US, which primarily uses imperial units (feet, pounds, gallons).
- How do I convert miles to kilometers?
- Multiply miles by 1.60934 to get kilometers. For example, 5 miles = 8.05 km, 10 miles = 16.09 km, and 26.2 miles (a marathon) = 42.16 km. For a quick mental estimate, multiply miles by 1.6. The reverse: multiply km by 0.621371 to get miles.
- Why does the US use a different measurement system?
- The US inherited the British Imperial system during colonial times and never fully transitioned to metric, despite Congress authorizing the switch in 1975. Today, the US uses metric in science, medicine, and military contexts, but everyday measurements (driving distances, cooking, body weight) remain in imperial units. This makes a converter useful for international communication.