Instantly convert between metric and imperial units — including millimeters, centimeters, meters, kilometers, inches, feet, yards, and miles. Enter a value and select your units to see accurate conversions in real time.
Conversion
Millimeters (mm)
Centimeters (cm)
Meters (m)
Kilometers (km)
Inches (in)
Feet (ft)
Yards (yd)
Miles (mi)
Millimeters (mm)
Centimeters (cm)
Meters (m)
Kilometers (km)
Inches (in)
Feet (ft)
Yards (yd)
Miles (mi)
Converted Value
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About the Length Converter
The Length Converter provides instant, accurate conversions between all common metric and imperial length units. Whether you're converting inches to centimeters for a clothing size, kilometers to miles for a road trip, or feet to meters for a construction project — this tool handles it with precision using established international conversion factors.
How Length Conversion Works
All units are first converted to a common base (meters), then converted to the target unit:
Converted Value = Input × (From unit in meters ÷ To unit in meters)
For example, converting 5 miles to kilometers: 5 × (1609.344 ÷ 1000) = 8.047 km.
Imperial / US Customary: Inches (in), Feet (ft), Yards (yd), Miles (mi)
Key Conversion Reference
1 inch = 2.54 cm = 25.4 mm
1 foot = 12 inches = 30.48 cm = 0.3048 m
1 yard = 3 feet = 36 inches = 0.9144 m
1 mile = 1,760 yards = 5,280 feet = 1,609.344 m = 1.609 km
1 meter = 100 cm = 1,000 mm ≈ 3.281 ft ≈ 1.094 yd
1 kilometer = 1,000 m ≈ 0.6214 miles ≈ 3,280.84 ft
Metric vs. Imperial: What's the Difference?
The metric system is the global standard, used by virtually every country for science, engineering, and everyday life. It scales cleanly by powers of 10: 10 mm = 1 cm, 100 cm = 1 m, 1,000 m = 1 km. This simplicity makes calculation and unit conversion straightforward.
The imperial system (used primarily in the United States) has less regular relationships — 12 inches to a foot, 3 feet to a yard, 1,760 yards to a mile — which makes mental math harder but remains deeply embedded in everyday US life (road signs, building materials, body height, screen sizes).
Common Height Conversions
5'0" = 152.4 cm
5'6" = 167.64 cm
5'10" = 177.8 cm
6'0" = 182.88 cm
6'4" = 193.04 cm
Real-World Uses
Construction & architecture — converting between feet and meters in building plans
Travel & navigation — converting km to miles for road trips or reading foreign speed limits. Also check the Temperature Converter for weather forecasts abroad.
Athletics & sports — track distances in meters vs. yards, height comparisons across countries
Clothing & sizing — converting height and inseam measurements between US and EU standards. For weight-based sizing, use the Weight Converter.
Science & education — working between SI units for physics or chemistry problems
Screens & displays — converting diagonal screen sizes between inches and centimeters
Frequently Asked Questions
How many centimeters are in an inch?
There are exactly 2.54 centimeters in one inch. This is the internationally defined standard. So 1 foot (12 inches) = 30.48 cm, and 1 yard (36 inches) = 91.44 cm.
How many feet are in a mile?
There are exactly 5,280 feet in one mile, or 1,760 yards. One mile equals approximately 1.609 kilometers.
How do you convert kilometers to miles?
Multiply kilometers by 0.621371. For example, 10 km × 0.621371 = 6.21 miles. To convert miles to km, multiply by 1.60934.
How many inches are in a foot?
There are exactly 12 inches in one foot. This is a foundational conversion in the imperial and US customary systems.
How many meters are in a yard?
One yard equals exactly 0.9144 meters. Conversely, one meter equals approximately 1.0936 yards.
At what height is 6 feet in centimeters?
6 feet = 182.88 centimeters. To convert feet to centimeters, multiply by 30.48. For example: 5'10" = (5 × 30.48) + (10 × 2.54) = 152.4 + 25.4 = 177.8 cm.
What is the difference between metric and imperial units?
The metric system (mm, cm, m, km) is a decimal-based system used in most countries worldwide. Everything scales by powers of 10: 10 mm = 1 cm, 100 cm = 1 m, 1,000 m = 1 km. Imperial units (inches, feet, yards, miles) use less regular multipliers (12 inches = 1 foot, 3 feet = 1 yard, 1,760 yards = 1 mile) and are primarily used in the United States.
How many millimeters are in a centimeter?
There are exactly 10 millimeters in one centimeter. 1 cm = 10 mm, 1 m = 100 cm = 1,000 mm, 1 km = 1,000 m = 1,000,000 mm.