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Convert between meters, feet, inches, centimeters, kilometers, miles, and yards instantly. Universal length converter for imperial and metric distance measurements.
2.54 cm
per Inch
3.28084 ft
per Meter
1.60934 km
per Mile
| Object/Distance | Inches | Centimeters | Feet | Meters |
|---|---|---|---|---|
| Penny diameter | 0.75 in | 1.91 cm | 0.06 ft | 0.02 m |
| Credit card width | 3.37 in | 8.56 cm | 0.28 ft | 0.09 m |
| Smartphone height | 6.00 in | 15.24 cm | 0.50 ft | 0.15 m |
| Letter paper (height) | 11.00 in | 27.94 cm | 0.92 ft | 0.28 m |
| Human foot (average) | 10.00 in | 25.40 cm | 0.83 ft | 0.25 m |
| Doorway height | 80.00 in | 203.20 cm | 6.67 ft | 2.03 m |
| Parking space length | 216.00 in | 548.60 cm | 18.00 ft | 5.49 m |
| Tennis court length | 936.00 in | 2377.00 cm | 78.00 ft | 23.77 m |
| Football field (100 yd) | 3600.00 in | 9144.00 cm | 300.00 ft | 91.44 m |
| City block (average) | 7920.00 in | 20117.00 cm | 660.00 ft | 201.17 m |
| 5K race | 196850.00 in | 500000.00 cm | 16404.00 ft | 5000.00 m |
| Marathon | 1660344.00 in | 4219470.00 cm | 138362.00 ft | 42194.70 m |
Length is the measurement of distance between two points. Throughout history, different civilizations developed their own systems of measuring length, leading to two dominant systems today: the imperial system (used primarily in the United States) and the metric system (used by most of the world). Each system has units suited for different scales of measurement, from tiny distances measured in millimeters to vast distances measured in miles or kilometers.
The imperial system includes inches (in), feet (ft), yards (yd), and miles (mi). An inch is defined as exactly 2.54 centimeters. A foot equals 12 inches, a yard equals 3 feet (36 inches), and a mile equals 5,280 feet. These units evolved from body-based measurements — the foot from the length of a human foot, the yard from the distance from nose to fingertip, and the inch from the width of a thumb. While less systematic than metric units, imperial measurements remain deeply embedded in American construction, sports, and everyday life.
The metric system uses millimeters (mm), centimeters (cm), meters (m), and kilometers (km). The meter is the fundamental unit, originally defined as one ten-millionth of the distance from the equator to the North Pole. Today it is defined more precisely using the speed of light. The beauty of the metric system lies in its simplicity: 10 millimeters = 1 centimeter, 100 centimeters = 1 meter, and 1,000 meters = 1 kilometer. This base-10 structure makes conversions straightforward and calculations easier, which is why the metric system is the international standard for science, engineering, and most global commerce.
Understanding both systems and how to convert between them is essential in our globalized world. Whether you are ordering materials from international suppliers, following a recipe from another country, interpreting architectural plans, or understanding athletic records, length conversion skills enable accurate communication and prevent costly mistakes.
Converting between length units requires multiplying by the appropriate conversion factor. The key conversion factors to memorize are: 1 inch = 2.54 cm, 1 foot = 0.3048 m, 1 meter = 3.28084 ft, and 1 mile = 1.60934 km. All other conversions can be derived from these fundamental relationships.
Question: A laptop screen measures 15.6 inches diagonally. What is this in centimeters?
Question: A European apartment listing shows a room that is 4.5 meters long. How many feet is that?
Tip: To convert decimal feet to feet and inches, multiply the decimal part by 12. Here: 0.76 × 12 ≈ 9.1 inches.
Question: A 10K race is 10 kilometers. What is this distance in miles?
Inches to centimeters: Multiply by 2.5 instead of 2.54 for a quick approximation (about 1.6% error).
Feet to meters: Divide by 3 instead of multiplying by 0.3048 (gives about 1.6% error).
Miles to kilometers: Multiply by 1.6 instead of 1.60934 (less than 1% error).
Kilometers to miles: Divide by 1.6 or multiply by 0.6 (about 3% error, good enough for estimates).
| Metric | Imperial Equivalent | Common Use |
|---|---|---|
| 1 cm | 0.394 inches | Small object dimensions |
| 10 cm | 3.94 inches | Phone width, photo size |
| 30 cm | 11.81 inches (≈1 ft) | Ruler length |
| 1 m | 3.28 feet | Counter height, doorway width |
| 2 m | 6.56 feet | Ceiling height |
| 100 m | 328 feet | Sprint distance |
| 1 km | 0.621 miles | Neighborhood walk |
| 5 km | 3.107 miles | Fun run distance |
| Imperial | Metric Equivalent | Common Use |
|---|---|---|
| 1 inch | 2.54 cm | Standard conversion reference |
| 6 inches | 15.24 cm | Sandwich length, tablet width |
| 1 foot | 30.48 cm | Ruler, shelf depth |
| 3 feet (1 yard) | 0.9144 m | Fabric, landscaping |
| 10 feet | 3.048 m | Room width, ceiling height |
| 100 feet | 30.48 m | Building length, lot width |
| 1 mile | 1.609 km | Running, driving distance |
| 10 miles | 16.09 km | Commute, cycling route |
| Event | Metric | Imperial |
|---|---|---|
| 100m dash | 100 meters | 328 feet |
| 400m track lap | 400 meters | 1,312 feet (0.249 mi) |
| 5K race | 5 kilometers | 3.107 miles |
| 10K race | 10 kilometers | 6.214 miles |
| Half marathon | 21.0975 km | 13.109 miles |
| Marathon | 42.195 km | 26.219 miles |
| Football field (US) | 91.44 meters | 100 yards (300 feet) |
| Baseball base distance | 27.432 meters | 90 feet |
International construction projects require converting between metric blueprints and imperial building codes. Material suppliers may list dimensions in different units. A single conversion error can result in costly material waste, structural problems, or project delays.
Aviation uses a mix of systems: altitude in feet, visibility in meters or miles, runway length in meters. Pilots and air traffic controllers must fluently convert between units to ensure safety. Travel distances are expressed differently across countries, requiring conversion for accurate trip planning.
Scientific publications universally use metric units, but older American research may use imperial measurements. Researchers must convert data accurately when comparing studies, replicating experiments, or collaborating internationally. Precision in conversion is critical for valid scientific conclusions.
Online shopping exposes consumers to products listed in various measurement systems. Furniture from Europe, electronics from Asia, and clothing from different countries all use different size standards. Accurate conversion prevents ordering items that do not fit or meet specifications.
Learn 1 inch = 2.54 cm, 1 foot = 0.3048 m, 1 mile = 1.609 km. All other conversions derive from these fundamentals.
Set up conversions so units cancel properly. For example: (5 miles) × (1.609 km / 1 mile) = 8.045 km. The "miles" cancel, leaving kilometers.
A meter is slightly longer than a yard, so meters should give a smaller number than feet. Miles are longer than kilometers, so kilometer values should be larger than mile values.
A common mistake is thinking inches and centimeters are roughly equal. In reality, 1 inch = 2.54 cm, so centimeters are much smaller. 10 inches is 25.4 cm, not 10 cm.
Converting from a larger unit to a smaller unit requires multiplication; smaller to larger requires division. Miles to kilometers: multiply by 1.609. Kilometers to miles: divide by 1.609 (or multiply by 0.621).
Never add or compare measurements in different units without converting first. Adding 5 feet + 2 meters gives a meaningless number. Convert to the same unit before performing arithmetic.
One inch equals exactly 2.54 centimeters. This conversion factor is internationally standardized and used worldwide. To convert inches to centimeters, multiply inches by 2.54. For example, 10 inches = 25.4 centimeters.
To convert meters to feet, multiply the number of meters by 3.28084. For example, 5 meters × 3.28084 = 16.4042 feet. For a quick estimate, multiply meters by 3.3, which gives a result accurate within 1% for most purposes.
Imperial units (inches, feet, yards, miles) are primarily used in the United States and were historically used throughout the British Empire. Metric units (millimeters, centimeters, meters, kilometers) are based on powers of 10 and used in most countries worldwide. The metric system is more consistent for scientific work because conversions involve simple multiplication or division by 10.
One mile equals exactly 5,280 feet. This comes from the statute mile definition established in 1593 by Queen Elizabeth I. To convert miles to feet, multiply miles by 5,280. For example, 2 miles = 10,560 feet.
To convert kilometers to miles, multiply kilometers by 0.621371. For example, 100 kilometers × 0.621371 = 62.1371 miles. A quick mental approximation is to multiply kilometers by 0.6 or divide by 1.6, which gives results within 3-4% accuracy.
A yard is an imperial unit equal to exactly 3 feet or 36 inches. One yard equals 0.9144 meters. Yards are commonly used in American football (100-yard field), fabric measurement, and landscaping. To convert yards to meters, multiply by 0.9144; to convert yards to feet, multiply by 3.
The metric system uses base-10 conversions, making calculations straightforward. For example, 1 kilometer = 1,000 meters, 1 meter = 100 centimeters. In contrast, imperial conversions require remembering irregular factors: 1 mile = 5,280 feet, 1 foot = 12 inches, 1 yard = 3 feet. This consistency makes metric units preferred in science, engineering, and international standards.
Online length converters are highly accurate when they use official conversion factors. Standard conversions like 1 inch = 2.54 cm exactly, 1 foot = 0.3048 meters exactly, and 1 mile = 1.609344 km exactly are defined by international standards. The precision displayed (typically 4-6 decimal places) is more than sufficient for virtually all practical applications including engineering, construction, and scientific research.
The meter is the most widely used length unit globally, as it is the base unit of length in the International System of Units (SI). Over 95% of the world's population lives in countries that officially use the metric system. Only the United States, Myanmar, and Liberia have not officially adopted the metric system, though even these countries use metric units in science, medicine, and international trade.
This calculator uses internationally recognized conversion factors defined by standards organizations. For critical applications in construction, engineering, surveying, or scientific research, always verify conversions using official measurement standards and consult with qualified professionals.