Length Calculator - Length Converter & Unit Conversion Calculator
Free length calculator & unit converter. Convert meters, feet, inches, kilometers, miles, centimeters, and more with accurate length conversions. Our calculator uses standard conversion factors for metric and imperial units including meters, kilometers, centimeters, millimeters, feet, inches, yards, and miles.
Last updated: December 15, 2024
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Enter the length value to convert
Conversion Result
100 Centimeters =
39.3700787402 Inches
Quick Conversions:
Common Equivalents:
- • 1 meter = 100 cm = 1000 mm
- • 1 kilometer = 1000 m ≈ 0.621 miles
- • 1 mile = 1.609 km = 5280 feet
- • 1 foot = 12 inches = 30.48 cm
- • 1 inch = 2.54 cm
- • 1 yard = 3 feet = 0.9144 m
Conversion Tips:
- • Metric system: Based on powers of 10 (easy conversion)
- • Imperial system: Uses fixed ratios (12 inches = 1 foot)
- • SI base unit for length is the meter (m)
- • Use dimensional analysis for complex conversions
- • Always check unit labels in calculations
Common Length Conversions
Conversion
1 m = 3.28084 ft
Standard metric to imperial length conversion
Conversion
1 in = 2.54 cm
Exact international definition
Conversion
1 km = 0.621371 mi
Common distance conversion
Conversion
1 ft = 0.3048 m
Exact conversion factor
Conversion
1 cm = 0.3937 in
Based on 1 in = 2.54 cm
Conversion
1 mi = 1.60934 km
Road distance conversion
Quick Example Result
Convert 100 centimeters to inches
Input
100 cm
Result
39.37 inches
100 cm ÷ 2.54 = 39.37 in
How Our Length Calculator Works
Our length calculator converts between units by using the meter as an intermediate reference. All length units are first converted to meters, then converted to the target unit. This ensures accuracy and consistency across all conversions.
Conversion Method
Step 1: Convert to Meters
Value in meters = Input × Conversion factor to metersStep 2: Convert to Target Unit
Result = Value in meters ÷ Target unit factorCommon Conversion Factors (to meters):
• 1 km = 1,000 m
• 1 cm = 0.01 m
• 1 mm = 0.001 m
• 1 mile = 1,609.344 m
• 1 yard = 0.9144 m
• 1 foot = 0.3048 m
• 1 inch = 0.0254 m
• 1 nautical mile = 1,852 m
Understanding Measurement Systems
The metric system (SI) is based on the meter and uses decimal prefixes (kilo-, centi-, milli-) for easy conversion. The imperial system uses traditional units with irregular conversion factors. In 1959, the international yard and pound agreement established exact conversions between systems, defining the inch as exactly 2.54 centimeters.
- Metric system uses powers of 10 for easy mental math
- Imperial system has historical origins with fixed ratios
- SI base unit for length is the meter (defined by speed of light)
- 1 inch = 2.54 cm exactly (international definition since 1959)
- Nautical mile based on Earth's circumference (1 minute of latitude)
- Light year is astronomical unit (distance light travels in one year)
Sources & References
- NIST Special Publication 811 - National Institute of Standards and TechnologyGuide for the Use of SI Units
- International System of Units (SI) - Bureau International des Poids et Mesures (BIPM)Official SI unit definitions and standards
- NIST - Unit Conversion ResourcesAuthoritative measurement conversion information
Need other conversion tools? Check out our percentage calculator and grams to cups calculator.
Get Custom Calculator for Your PlatformLength Conversion Examples
Metric Conversions:
- 1 km: 1,000 m = 100,000 cm
- 1 m: 100 cm = 1,000 mm
- 1 cm: 10 mm = 10,000 μm
- 1 mm: 1,000 μm = 1,000,000 nm
Imperial Conversions:
- 1 mile: 5,280 ft = 1,760 yd
- 1 yard: 3 ft = 36 in
- 1 foot: 12 in = 30.48 cm
- 1 inch: 2.54 cm = 25.4 mm
Cross-System Conversions:
5 km = 3.107 miles
100 m = 328.08 feet
6 feet = 182.88 cm
50 in = 127 cm
Marathon Distance
26.2 miles
= 42.195 kilometers (Olympic standard)
Human Height
6 feet tall
= 1.8288 meters = 182.88 cm
Frequently Asked Questions
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