Convert between different units of measurement instantly. Supports Length, Weight, Volume, Temperature, and Speed conversions.
| Input | From | To | Result |
|---|---|---|---|
| 1 | Meter | Kilometer | 0.001 |
| 1 | Meter | Centimeter | 100 |
| 1 | Meter | Millimeter | 1.00K |
| 1 | Meter | Mile | 6.214e-4 |
| 1 | Meter | Yard | 1.093613 |
| 1 | Meter | Foot | 3.28084 |
| 1 | Meter | Inch | 39.370079 |
Master unit conversions for length, weight, volume, temperature, and speed. Learn conversion formulas, understand different measurement systems, and solve practical conversion problems.
Convert between metric (meters, kilometers) and imperial (feet, miles) length units
Convert between metric (grams, kilograms) and imperial (pounds, ounces) weight units
Convert liquid volumes and capacities between different measurement systems
Convert between Celsius, Fahrenheit, and Kelvin temperature scales
Convert speed measurements between different units
International System of Units used worldwide, based on powers of 10
Meter (m), Kilogram (kg), Second (s), Kelvin (K)
Used officially by almost all countries; the USA primarily uses US Customary units
Traditional system of weights and measures originating from the British Empire
Foot, Pound, Second, Fahrenheit
Limited use in the UK; closely related US Customary System used in the USA
Similar to imperial but with some differences, used in the United States
Similar to Imperial but with different definitions
United States exclusively
Slight variations from Imperial system in volume measurements
A recipe calls for 2 cups of flour, but you only have a metric scale
Convert 2 cups to grams: 2 cups × 120g/cup = 240g of flour
Use 120g per cup for flour, but check specific ingredient densities
Planning a road trip: distance is 300 miles, speed limit is 110 km/h
Convert miles to km: 300 × 1.609 = 482.8 km. Travel time: 482.8 ÷ 110 = 4.39 hours
Use 1.61 for quick mile to km conversions
Weather forecast says 25°C, but you're used to Fahrenheit
Convert to Fahrenheit: (25 × 9/5) + 32 = 77°F
Quick approximation: Double °C and add 30 to get approximate °F (less accurate at extremes)
You ran 5 kilometers but want to know the distance in miles
Convert km to miles: 5 × 0.621 = 3.1 miles
For rough conversions, 8 km ≈ 5 miles, useful for running distances
To convert inches to centimeters, multiply the inch value by 2.54. For example, 10 inches = 25.4 cm.
To convert centimeters to inches, divide the centimeter value by 2.54. For example, 25.4 cm = 10 inches.
To convert kilometers to miles, multiply the kilometer value by 0.621371. For example, 5 km = 3.11 miles.
To convert pounds to kilograms, multiply the pound value by 0.453592. For example, 10 pounds = 4.54 kg.
Different systems developed independently in various cultures. The metric system was created during the French Revolution for standardization, while imperial units evolved from traditional measurements used in the British Empire.
Most conversion factors are precise to many decimal places. For everyday use, 2-3 decimal places are sufficient. Scientific and engineering applications may require more precision.
Dimensional analysis is a method of converting units by multiplying by conversion factors that equal 1 (like 1000m/1km). This ensures units cancel correctly and helps avoid errors in complex conversions.
You can only convert between units that measure the same physical quantity. For example, you cannot convert meters to kilograms because they measure different things (length vs. mass).
SI prefixes are standard multipliers for metric units: kilo- (1000×), centi- (1/100), milli- (1/1000), micro- (1/1,000,000), mega- (1,000,000×), etc. They make metric conversions very simple.
The US retains imperial units due to historical reasons, infrastructure costs of changing, and cultural familiarity. However, most scientific and medical fields in the US use metric units.
The meter was originally defined as one ten-millionth of the distance from the equator to the North Pole
Until 2019, the kilogram was defined by a physical artifact. Since 2019, it is defined using the Planck constant.
Fahrenheit scale was based on three fixed points: 0°F (freezing point of brine), 32°F (water freezing), 96°F (human body temperature)
The metric system became legal in the United States in 1866, but was never made mandatory
The International System of Units (SI) has seven base units: meter (length), kilogram (mass), second (time), ampere (electric current), kelvin (temperature), mole (amount of substance), and candela (luminous intensity). All other units are derived from these seven.
Most countries have officially adopted the metric system. Even countries that still use imperial units officially define them in terms of metric units. This ensures global consistency in trade, science, and technology.
Remember: When in doubt, use metric units for international communication and double-check conversion factors for critical applications.
| Category | From Unit | To Unit | Multiply By |
|---|---|---|---|
| Length | Miles | Kilometers | 1.60934 |
| Length | Feet | Meters | 0.3048 |
| Weight | Pounds | Kilograms | 0.453592 |
| Weight | Ounces | Grams | 28.3495 |
| Volume | US Gallons | Liters | 3.78541 |
| Volume | Fluid Ounces | Milliliters | 29.5735 |
| Speed | MPH | KPH | 1.60934 |
| Temperature | °C to °F | Formula | (°C × 9/5) + 32 |
| Temperature | °F to °C | Formula | (°F - 32) × 5/9 |
Note: For temperature conversions, use the formulas provided. Other conversions use multiplication factors.
This unit converter helps you convert inches to cm, cm to inches, kilometers to miles, miles to kilometers, and pounds to kg instantly with accurate formulas and conversion tables.