Length Converter
Convert any length between metric and imperial units: millimeters, centimeters, meters, kilometers, inches, feet, yards, miles, and nautical miles.
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How to use Length Converter
- Enter a length in its row — a height in feet, a distance in km, or any of the nine units.
- The mm, cm, m, km, inch, foot, yard, mile, and nautical-mile rows all recalculate together.
- For a height like 5 ft 9 in, convert the feet and inches to total inches first (5 × 12 + 9 = 69), then enter 69 in the inch row.
- Working from a marine or aviation chart, drive from the nautical-mile row — at 1,852 m exactly, it ties to one minute of latitude and will not match a statute mile.
Length converter: metric and imperial distance units
This converter translates any length across nine units, covering both metric (millimeters, centimeters, meters, kilometers) and imperial/US customary (inches, feet, yards, miles), plus the nautical mile used at sea and in the air. Enter a distance in one row and the rest are derived from it. Below are the exact factors and the situations where each unit is the natural choice.
The exact conversion factors
- 1 inch = 2.54 cm = 0.0254 m
- 1 foot = 12 inches = 0.3048 m
- 1 yard = 3 feet = 0.9144 m
- 1 mile = 1,760 yards = 5,280 feet = 1,609.344 m
- 1 meter = 3.28084 ft = 39.3701 in
- 1 kilometer = 0.621371 miles
- 1 nautical mile = 1,852 m = 1.15078 statute miles
Since 1959 the inch has been defined as exactly 2.54 cm by international agreement, so these imperial-to-metric factors are not approximations — they are precise definitions.
Everyday metric and imperial swaps
The conversions people reach for most are inches to centimeters (for screen sizes, lumber, and clothing), feet to meters (for room dimensions and heights), and miles to kilometers (for travel and running). A quick mental rule for miles to km is to add about 60%: 10 miles is roughly 16 km. For a rough km-to-miles estimate, multiply by 0.6.
Height conversions
Heights given in feet and inches need a two-step conversion: turn the whole height into inches, then multiply by 2.54 for centimeters. For example 6 ft 0 in is 72 in = 182.88 cm. This is the single most common length conversion online, and getting the feet-plus-inches step right is where most errors creep in.
Navigation and the nautical mile
Pilots and sailors use the nautical mile because it ties directly to latitude: one nautical mile equals one minute of arc along a meridian. Speeds in knots are nautical miles per hour. If you are reading a marine chart in nautical miles but planning fuel in kilometers, convert by multiplying nautical miles by 1.852.
Related converters
- Area Converter — once you have lengths, compute floor area or land size.
- Speed Converter — pair distance with time for mph, km/h, and knots.
- Volume Converter — for three-dimensional capacity in liters and gallons.
Frequently asked questions
How do I convert inches to centimeters?
How many feet are in a meter?
How do I convert miles to kilometers?
What is a nautical mile and why is it different?
Why are some results shown in scientific notation?
How accurate are these conversions?
How tall is 5 feet 9 inches in centimeters?
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