Length Converter
Convert between metric and imperial length units instantly
Universal Length Converter
Convert From
Convert To
Length Conversion Table
Metric to Imperial Conversions
Imperial to Metric Conversions
Length Conversion Chart
Meters to Feet
- 1 m = 3.281 ft
- 2 m = 6.562 ft
- 3 m = 9.843 ft
- 5 m = 16.404 ft
- 10 m = 32.808 ft
- 20 m = 65.617 ft
- 50 m = 164.042 ft
- 100 m = 328.084 ft
Feet to Meters
- 1 ft = 0.305 m
- 3 ft = 0.914 m
- 5 ft = 1.524 m
- 10 ft = 3.048 m
- 20 ft = 6.096 m
- 50 ft = 15.24 m
- 100 ft = 30.48 m
- 500 ft = 152.4 m
Inches to Centimeters
- 1 in = 2.54 cm
- 2 in = 5.08 cm
- 5 in = 12.7 cm
- 10 in = 25.4 cm
- 12 in = 30.48 cm
- 24 in = 60.96 cm
- 36 in = 91.44 cm
- 48 in = 121.92 cm
Kilometers to Miles
- 1 km = 0.621 mi
- 5 km = 3.107 mi
- 10 km = 6.214 mi
- 25 km = 15.534 mi
- 50 km = 31.069 mi
- 100 km = 62.137 mi
- 200 km = 124.274 mi
- 500 km = 310.686 mi
Inch Definition
The inch is a unit of length in the imperial and United States customary systems of measurement, defined as exactly 2.54 centimeters since the international yard and pound agreement of 1959. Historically derived from the width of a human thumb, the inch has evolved into a precisely standardized measurement used primarily in the United States, United Kingdom, and Canada for various applications including construction, manufacturing, and everyday measurements.
One inch is subdivided into smaller fractional parts using binary divisions: halves, quarters, eighths, sixteenths, thirty-seconds, and sixty-fourths. These divisions appear as graduations on rulers, tape measures, and other measuring instruments. The inch symbol is represented by a double prime mark (″) or quotation marks ("), commonly written as 1″ or 1". Twelve inches equal one foot, making the inch a fundamental component of the imperial measurement system for shorter length measurements.
Standard Conversion
\[ 1 \text{ inch} = 2.54 \text{ centimeters (exactly)} \]
\[ 1 \text{ inch} = 25.4 \text{ millimeters} \]
Feet Definition
The foot is a unit of length in the imperial and United States customary measurement systems, historically based on the length of a human foot. Since the international yard and pound agreement of 1959, one foot is officially defined as exactly 0.3048 meters or 30.48 centimeters. The foot remains a primary unit for measuring height, distance, and dimensions in countries using the imperial system, particularly the United States where it dominates construction, real estate, aviation, and everyday measurements.
One foot contains exactly 12 inches and three feet equal one yard. The plural form "feet" refers to more than one foot, while the singular "foot" represents a single unit. The foot is abbreviated as "ft" or represented by a prime symbol (′), commonly written as 1′ or 1 ft. Linear feet measurements are used extensively in construction for materials like lumber, flooring, and trim, while square feet measure area and cubic feet measure volume in imperial applications.
Standard Conversion
\[ 1 \text{ foot} = 0.3048 \text{ meters (exactly)} \]
\[ 1 \text{ foot} = 12 \text{ inches} \]
\[ 1 \text{ foot} = 30.48 \text{ centimeters} \]
Meter Definition
The meter (or metre in British English) is the base unit of length in the International System of Units (SI) and the metric system. According to the most recent definition adopted in 2019, the meter is defined as the distance light travels in a vacuum during a time interval of exactly 1/299,792,458 of a second. This definition ties the meter to fundamental physical constants, making it an absolute and unchanging standard that can be reproduced in any properly equipped laboratory worldwide.
The meter is the foundation of the metric system's length measurements, with larger and smaller units formed by adding standard prefixes. Kilometers (1000 meters) measure longer distances, centimeters (1/100 meter) and millimeters (1/1000 meter) measure shorter lengths, creating a decimal-based system that simplifies calculations. The meter is abbreviated as "m" and is used globally in science, engineering, education, and most countries' everyday measurements, representing the international standard for length measurement.
Standard Conversion
\[ 1 \text{ meter} = 3.28084 \text{ feet} \]
\[ 1 \text{ meter} = 39.3701 \text{ inches} \]
\[ 1 \text{ meter} = 100 \text{ centimeters} \]
Imperial / US Measurement System
The imperial system is a collection of measurement units that originated in the British Empire and spread to former colonies including the United States, Canada, and others. The United States uses a variation called the United States customary units, which differs slightly from the British imperial system in volume measurements but uses identical length units. The imperial system for length is based on inches, feet, yards, and miles, with non-decimal relationships between units that reflect historical usage patterns and practical division methods.
Imperial Length Units
- 12 inches = 1 foot
- 3 feet = 1 yard
- 5,280 feet = 1 mile
- 1,760 yards = 1 mile
- 36 inches = 1 yard
The imperial system uses irregular conversion factors between units, requiring memorization of specific relationships rather than simple decimal multiplication. This complexity stems from historical origins where units developed independently for different applications before standardization efforts unified them. While the system presents challenges for calculations compared to the decimal-based metric system, its divisions often align with practical halving and quartering operations common in construction and manufacturing, where binary fractions like 1/2, 1/4, 1/8, and 1/16 are frequently used.
Today, the United States remains the primary country using imperial measurements for everyday applications, though Canada and the United Kingdom have officially adopted the metric system while maintaining some imperial usage in specific contexts. The imperial system persists in American construction, real estate, transportation, sports, and personal measurements like height and weight. International trade and scientific collaboration require conversion between imperial and metric systems, making length converters essential tools for global communication and commerce.
Metric Measurement System
The metric system, officially known as the International System of Units (SI), is a decimal-based measurement system used by virtually every country worldwide except the United States. Developed in France during the late 18th century, the metric system revolutionized measurement by establishing units based on natural phenomena and using consistent base-10 scaling. The meter serves as the fundamental unit for length, with all other length units derived by multiplying or dividing by powers of ten, creating an intuitive and mathematically elegant system.
Metric Length Units
- 1 kilometer (km) = 1,000 meters
- 1 meter (m) = 100 centimeters
- 1 meter (m) = 1,000 millimeters
- 1 centimeter (cm) = 10 millimeters
- 1 millimeter (mm) = 1,000 micrometers
The metric system uses standardized prefixes to indicate scale: kilo- (1000), centi- (1/100), and milli- (1/1000) are the most common for length measurements. These prefixes apply consistently across all measurement types, allowing someone familiar with kilometers to immediately understand kilowatts or kilograms. Conversions within the metric system require only moving decimal points, eliminating the need for complex multiplication or division and reducing calculation errors compared to imperial conversions.
The metric system's advantages include universal adoption, scientific precision, ease of teaching and learning, compatibility with digital systems, and seamless integration with mathematics. Scientists, engineers, and international organizations exclusively use metric measurements for technical work, research, and global standards. The system's base-10 structure aligns naturally with decimal notation and calculator operations, making it ideal for modern computation and international collaboration across borders, industries, and disciplines.
What is Length Conversion?
Length conversion is the mathematical process of transforming a measurement expressed in one unit of length into its equivalent value in a different unit of length. This conversion maintains the actual physical distance while changing the numerical value and unit label to match different measurement systems or scales. Length conversions are necessary when working across international borders, translating technical specifications, comparing measurements from different sources, or adapting plans and designs to local measurement standards.
Two primary types of length conversions exist: conversions within the same measurement system and conversions between different measurement systems. Within-system conversions include changing kilometers to meters or feet to inches, typically involving simple multiplication or division by standard factors. Between-system conversions translate imperial measurements to metric or vice versa, requiring conversion factors established by international agreements like the 1959 international yard and pound agreement that fixed the relationship between imperial and metric units.
Accurate length conversion requires using precise conversion factors and maintaining appropriate significant figures throughout calculations. Rounding errors can accumulate in multi-step conversions, particularly when converting back and forth between systems. Professional applications in engineering, construction, manufacturing, and science demand high-precision conversions to ensure safety, compatibility, and quality. Modern length converters automate these calculations, providing instant, accurate results that eliminate human error and streamline workflows across global projects and international collaboration.
Conversion Formulae
Metric to Imperial Conversions
Meters to Feet:
\[ \text{Feet} = \text{Meters} \times 3.28084 \]
Example: 10 m = 10 × 3.28084 = 32.8084 ft
Centimeters to Inches:
\[ \text{Inches} = \text{Centimeters} \times 0.393701 \]
Example: 100 cm = 100 × 0.393701 = 39.3701 in
Kilometers to Miles:
\[ \text{Miles} = \text{Kilometers} \times 0.621371 \]
Example: 100 km = 100 × 0.621371 = 62.1371 mi
Imperial to Metric Conversions
Feet to Meters:
\[ \text{Meters} = \text{Feet} \times 0.3048 \]
Example: 10 ft = 10 × 0.3048 = 3.048 m
Inches to Centimeters:
\[ \text{Centimeters} = \text{Inches} \times 2.54 \]
Example: 12 in = 12 × 2.54 = 30.48 cm
Miles to Kilometers:
\[ \text{Kilometers} = \text{Miles} \times 1.609344 \]
Example: 10 mi = 10 × 1.609344 = 16.09344 km
Within-System Conversions
Feet to Inches:
\[ \text{Inches} = \text{Feet} \times 12 \]
Meters to Centimeters:
\[ \text{Centimeters} = \text{Meters} \times 100 \]
Kilometers to Meters:
\[ \text{Meters} = \text{Kilometers} \times 1000 \]
Uses of Length Conversion
Construction and Architecture
Construction professionals convert between imperial and metric measurements when working with international building codes, imported materials, or global design standards. Architects translate client requirements, engineers verify structural calculations, and contractors adapt blueprints to match local measurement conventions and material availability.
International Trade and Commerce
Global businesses require length conversions for product specifications, shipping dimensions, packaging requirements, and customs documentation. Manufacturers convert design specifications, logistics companies calculate shipping volumes, and retailers adapt product descriptions to match customer expectations in different markets using various measurement systems.
Engineering and Manufacturing
Engineers convert measurements when collaborating across borders, using international components, or following global standards. Manufacturing operations require precise conversions for machining tolerances, quality control specifications, and assembly instructions. Automotive, aerospace, and electronics industries constantly translate between measurement systems to ensure compatibility and compliance.
Education and Science
Students learn unit conversions as fundamental mathematical skills while scientists require precise conversions for research collaboration, data sharing, and publication in international journals. Educational materials often present measurements in both systems, helping students develop fluency with multiple measurement conventions and understand mathematical conversion principles.
Travel and Transportation
Travelers convert distances, heights, and dimensions when navigating between countries using different measurement systems. Aviation uses feet for altitude while meteorology uses meters, requiring pilots and air traffic controllers to convert rapidly. Road distances, speed limits, and vehicle dimensions require conversion for international drivers and transportation planners.
Sports and Athletics
International sporting events convert track lengths, swimming pool dimensions, and field measurements between systems. Olympic standards use metric measurements while American sports often use imperial units. Athletes, coaches, and sports journalists translate performance metrics, training distances, and competition results for global audiences and comparative analysis.
How to Use the Length Converter
Step-by-Step Instructions
Basic Conversion Process
- Enter the numerical value you want to convert in the "Convert From" input field
- Select the current unit of measurement from the "Convert From" dropdown menu
- Choose your desired target unit from the "Convert To" dropdown menu
- Click the "Convert" button to calculate the conversion
- View the converted result displayed in the output field with the conversion formula shown below
Selecting Units
The converter organizes units into two categories for easy selection:
- Metric Units: Millimeter, Centimeter, Meter, Kilometer
- Imperial Units: Inch, Foot, Yard, Mile
Choose units from the same category for within-system conversions or different categories for between-system conversions.
Understanding Results
The converter provides comprehensive results:
- The converted value appears in the output field with appropriate precision
- The conversion formula displays below showing the mathematical operation
- Results update automatically when you change input values or units
- The calculator maintains accuracy to multiple decimal places for precision work
Pro Tip: For quick calculations, the converter automatically performs conversions as you change values. Use the conversion tables and charts above for quick reference when you need common conversions without entering specific values. The calculator uses internationally accepted conversion factors established by the 1959 international yard and pound agreement for maximum accuracy.
Frequently Asked Questions
1. How many feet are in a meter?
One meter equals exactly 3.28084 feet. This conversion factor is defined by the 1959 international yard and pound agreement, which established that one foot equals 0.3048 meters precisely. To convert meters to feet, multiply the meter value by 3.28084, or divide feet by 3.28084 to get meters.
2. How do I convert inches to centimeters?
Multiply the number of inches by 2.54 to get centimeters. This is an exact conversion: 1 inch equals exactly 2.54 centimeters by international definition. For example, 10 inches equals 10 × 2.54 = 25.4 centimeters. To reverse the conversion, divide centimeters by 2.54 to get inches.
3. What is the difference between imperial and metric systems?
The imperial system uses irregular conversion factors (12 inches per foot, 3 feet per yard) based on historical standards, while the metric system uses consistent base-10 scaling (10 mm per cm, 100 cm per meter). The metric system is decimal-based, making calculations simpler, while imperial uses fractional divisions that align with practical halving operations common in manual work.
4. How many centimeters are in one foot?
One foot equals exactly 30.48 centimeters. This is derived from the relationship that 1 foot = 0.3048 meters, and since 1 meter = 100 centimeters, therefore 1 foot = 30.48 cm. This conversion is precise and internationally standardized for all length measurements and engineering applications.
5. What countries use the imperial system?
The United States is the primary country using the imperial system (specifically US customary units) for everyday measurements. The United Kingdom officially uses the metric system but retains imperial measurements for road distances and some traditional applications. Liberia and Myanmar also use imperial measurements, though many countries transitioning from imperial to metric maintain dual systems during the change.
6. How do I convert kilometers to miles?
Multiply kilometers by 0.621371 to get miles, or multiply miles by 1.609344 to get kilometers. For example, 100 kilometers equals 100 × 0.621371 = 62.1371 miles. A quick approximation is that 5 kilometers roughly equals 3 miles, useful for mental calculations when traveling between countries using different systems.
7. Why is the metric system considered easier to use?
The metric system uses base-10 scaling, meaning conversions only require moving decimal points rather than memorizing irregular factors. Converting 1.5 kilometers to meters simply means moving the decimal three places (1,500 meters), while converting 1.5 miles to feet requires knowing that 1 mile = 5,280 feet and multiplying (7,920 feet). This decimal structure reduces errors and simplifies calculations.
8. How accurate are online length converters?
Professional online length converters use internationally standardized conversion factors and provide accuracy to many decimal places, typically far exceeding the precision needed for most applications. The conversion factors themselves are exact definitions established by international agreement, so any reputable calculator provides the same accurate results. Rounding only affects display precision, not the underlying calculation.
9. What is the meter based on?
Since 2019, the meter is defined as the distance light travels in a vacuum during exactly 1/299,792,458 of a second. This definition ties the meter to the speed of light, a fundamental physical constant. Earlier definitions included one ten-millionth of the distance from the equator to the North Pole and the wavelength of specific light emissions, evolving toward increasingly precise physical standards.
10. How many inches are in a yard?
One yard equals exactly 36 inches. This relationship comes from the fact that 1 yard = 3 feet and 1 foot = 12 inches, therefore 3 × 12 = 36 inches per yard. The yard is commonly used in American football field measurements and fabric sales, while construction more frequently uses feet and inches for detailed measurements.