Length Converter: Meters, Feet, Inches, Miles
Convert between metric and imperial length units instantly. Supports millimeters, centimeters, meters, kilometers, inches, feet, yards, and miles. Convert area units with the Area Converter, or explore all measurement categories at our Unit Converter.
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How it works
This converter uses exact mathematical ratios to translate between length units. All conversions are based on the international definitions: one inch equals exactly 25.4 millimeters, one foot is 12 inches (0.3048 m), one yard is 3 feet (0.9144 m), and one mile is 5,280 feet (1,609.344 m). Metric units scale by powers of ten: 1 km = 1,000 m = 100,000 cm = 1,000,000 mm.
Enter a value in either field and the converter instantly calculates the result. Use the swap button to reverse the conversion direction. The quick reference table and all-to-all matrix provide common values at a glance.
How Length Conversion Works
Length conversion translates a measurement from one unit to another using fixed mathematical ratios. The metric system uses powers of ten: 1 kilometer equals 1,000 meters, and 1 meter equals 100 centimeters. Imperial units follow less uniform ratios: 1 mile is 5,280 feet, 1 yard is 3 feet, and 1 foot is 12 inches. Conversions between the two systems rely on the international inch, defined as exactly 25.4 millimeters since 1959. To convert, multiply or divide by the appropriate factor. For instance, centimeters to inches requires dividing by 2.54, while kilometers to miles uses a factor of 0.621371.
Common Length Conversions
The most frequently searched length conversions include centimeters to inches (body measurements, screen sizes), feet to meters (room dimensions, height), miles to kilometers (road distances, running), and yards to meters (sports fields, fabric). People converting between metric and imperial systems often need these for travel, online shopping, fitness tracking, and home improvement projects. Knowing that 1 inch is exactly 2.54 cm, 1 foot is 30.48 cm, and 1 mile is 1.609 km covers the vast majority of everyday conversion needs.
When You Need Length Conversion
Length conversion arises in everyday situations more often than most people realize. Travelers between the US and Europe need to convert miles to kilometers for road signs and speed limits. Online shoppers convert clothing sizes and furniture dimensions between inches and centimeters. Athletes track race distances — a 5K is 3.107 miles, and a marathon is 42.195 kilometers. Construction and DIY projects frequently mix metric and imperial measurements, especially when using international building materials. Screen sizes are universally measured in diagonal inches, while European product specifications list dimensions in centimeters.
Length Units Around the World
Most countries use the metric system (meters, kilometers) as their official measurement standard. The United States, Liberia, and Myanmar are the only nations that still primarily use imperial units (miles, feet, inches) in daily life. The United Kingdom uses a hybrid system: road distances are in miles, but product labels and construction plans use meters and centimeters. Aviation worldwide uses feet for altitude and nautical miles for distance. Maritime navigation also relies on nautical miles, where 1 nautical mile equals exactly 1,852 meters or 1.151 statute miles.
Tips for Accurate Length Conversion
Always use the exact conversion factor rather than rounded approximations. The difference between using 2.54 and 2.5 for inch-to-centimeter conversion compounds with larger values. When converting for construction or engineering, maintain at least two decimal places. For everyday use, rounding to one decimal place is usually sufficient. Double-check whether a measurement refers to a US or UK standard — while inches and feet are identical, other units may differ. When converting multiple dimensions (like room size), convert each dimension separately rather than converting the final area, as this avoids compounding rounding errors.
Practical Examples
A person who is 5 feet 9 inches tall measures 175.26 centimeters. A 65-inch TV has a diagonal of 165.1 centimeters. The distance from New York to Los Angeles is approximately 2,451 miles or 3,944 kilometers. A standard sheet of A4 paper measures 210 x 297 millimeters, while US Letter size is 8.5 x 11 inches (215.9 x 279.4 mm). A football field is 100 yards or 91.44 meters long. A half marathon covers 13.1 miles or 21.1 kilometers.
FAQ
- How do I convert centimeters to inches?
- Divide the centimeter value by 2.54. For example, 10 cm / 2.54 = 3.937 inches. The conversion factor comes from the international definition of one inch as exactly 25.4 millimeters, adopted in 1959.
- How many feet are in a meter?
- One meter equals exactly 3.28084 feet. To convert meters to feet, multiply by 3.28084. To convert feet to meters, multiply by 0.3048. One foot is defined as exactly 0.3048 meters.
- How do I convert miles to kilometers?
- Multiply the number of miles by 1.609344 to get kilometers. For example, 10 miles x 1.609344 = 16.09344 km. For a quick mental estimate, multiply miles by 1.6. To convert kilometers to miles, divide by 1.609344 or multiply by 0.621371.
- What is the difference between metric and imperial length units?
- The metric system (millimeters, centimeters, meters, kilometers) is based on powers of ten and used by most countries worldwide. The imperial system (inches, feet, yards, miles) uses irregular ratios: 12 inches per foot, 3 feet per yard, 1,760 yards per mile. The US, Liberia, and Myanmar are the only countries that primarily use imperial units in daily life.
- How tall is 6 feet in centimeters?
- Six feet equals exactly 182.88 centimeters. The calculation is: 6 feet x 30.48 cm per foot = 182.88 cm. For height conversion, 5 feet 10 inches = 177.8 cm, 5 feet 11 inches = 180.34 cm, and 6 feet 1 inch = 185.42 cm.
- How do I convert yards to meters?
- Multiply the number of yards by 0.9144 to get meters. One yard is defined as exactly 0.9144 meters (or 91.44 centimeters). For example, 100 yards x 0.9144 = 91.44 meters. A football field is 100 yards or 91.44 meters long.
- How many millimeters are in an inch?
- One inch equals exactly 25.4 millimeters. This is an exact definition, not an approximation. To convert inches to millimeters, multiply by 25.4. To convert millimeters to inches, divide by 25.4. For example, 5 mm / 25.4 = 0.1969 inches.
- What is a nautical mile and how does it relate to other length units?
- A nautical mile equals exactly 1,852 meters (1.852 km or 1.15078 statute miles). It is used in aviation and maritime navigation because it corresponds to approximately one minute of latitude on the Earth's surface. It is not part of the imperial system and differs from the statute mile (1,609.344 meters) used on roads.
- How do I convert kilometers to miles for driving distances?
- Divide the distance in kilometers by 1.609344 to get miles. For quick mental math, divide by 1.6 or multiply by 0.625. For example, a 100 km drive is about 62.1 miles. Speed limit signs showing 120 km/h correspond to approximately 74.6 mph.
- How do I convert height from feet and inches to centimeters?
- First convert everything to inches (feet x 12 + inches), then multiply by 2.54 to get centimeters. For example, 5 feet 7 inches = 67 inches x 2.54 = 170.18 cm. Alternatively, convert feet to cm (x 30.48) and inches to cm (x 2.54) separately, then add them together.
- What are the most common room dimension conversions?
- A 10 x 12 foot room is 3.05 x 3.66 meters (11.15 m2 or 120 ft2). A 4 x 5 meter room is 13.12 x 16.40 feet. For carpet or flooring calculations, 1 square meter equals 10.764 square feet. When shopping for furniture internationally, convert each dimension separately to ensure proper fit.
- How are running distances measured in metric and imperial?
- Common race distances have standard conversions: 5K = 3.107 miles, 10K = 6.214 miles, half marathon = 13.109 miles (21.0975 km), and a full marathon = 26.219 miles (42.195 km). Track events use metric distances: the 100-meter dash, 400-meter relay, and 1,500 meters (often called the "metric mile" though it is shorter than a mile).
- How do screen sizes convert between inches and centimeters?
- Screen sizes are measured diagonally in inches worldwide. A 55-inch TV has a diagonal of 139.7 cm. A 27-inch monitor is 68.58 cm. A 6.7-inch phone screen is 17.02 cm. To convert, multiply inches by 2.54. The aspect ratio (16:9, 21:9) does not affect the diagonal measurement.
- What paper sizes are used in different countries and how do they compare?
- The international A4 paper size is 210 x 297 mm (8.27 x 11.69 inches). The US Letter size is 8.5 x 11 inches (215.9 x 279.4 mm). A4 is slightly narrower and taller than US Letter. The international A series follows a consistent ratio (1:sqrt(2)), while US paper sizes are based on inches and lack a systematic scaling relationship.
- What is the difference between a US survey foot and an international foot?
- The international foot is exactly 0.3048 meters (304.8 mm). The US survey foot was 1200/3937 meters (approximately 304.800609 mm), making it about 0.61 mm longer per 1,000 feet. The US officially retired the survey foot on January 1, 2023, and now uses only the international foot. The difference mattered in large-scale land surveys but was negligible for everyday use.
- How do I convert between small length units for precision work?
- For precision measurement: 1 inch = 25.4 mm, 1 mm = 0.03937 inches, 1 micrometer (micron) = 0.001 mm = 0.0000394 inches, and 1 mil (thou) = 0.001 inches = 0.0254 mm. Machinists often work in thousandths of an inch (mils), while metric engineering uses micrometers. A human hair is about 70 micrometers or 2.8 mils thick.