Tool guide
How to use the Length Converter
Length conversion works most reliably when every supported unit is related to one common base unit. This converter uses the meter as that base, applies decimal powers for nanometers through kilometers, and uses the exact international definitions for inches, feet, yards, statute miles, and international nautical miles. It also includes a separate feet-and-inches mode so a compound measurement such as 5 ft 8 in does not need to be converted into a decimal foot value first.
People also use this tool for
People also use this length converter to change centimeters to inches, inches to centimeters, feet to meters, meters to feet, kilometers to miles, miles to kilometers, millimeters to inches, feet and inches to centimeters, nautical miles to kilometers, and small metric measurements for school, travel, construction, shopping, crafts, fitness, maps, and technical work.
What this tool is useful for
- Convert metric and international inch-pound lengths for travel, school, crafts, construction estimates, product dimensions, maps, running distances, and everyday comparisons.
- Enter a compound feet-and-inches measurement and convert it directly to centimeters, meters, inches, or any other supported unit.
- Compare nanometers, micrometers, millimeters, centimeters, meters, kilometers, inches, feet, yards, statute miles, and international nautical miles in one result.
Practical example
To convert 5 ft 8 in to centimeters, first combine the measurement as 5 × 12 + 8 = 68 inches. Because one international inch is exactly 0.0254 meter, 68 × 0.0254 = 1.7272 meters, or exactly 172.72 centimeters. Displaying 172.7 cm would be a rounded presentation of that same conversion, not a different conversion factor.
Helpful tips
- Check whether the source measurement is a statute mile or a nautical mile; they are different units and are not interchangeable.
- Metric prefixes are powers of ten: milli means one-thousandth, centi means one-hundredth, and kilo means one thousand.
- Choose enough displayed decimals for the original measurement's precision. Extra decimal places do not make an imprecise source measurement more accurate.
- The standard-unit mode preserves a negative sign for mathematical differences or coordinates, although a physical length or distance is ordinarily nonnegative.
- For surveying records, confirm whether a historical U.S. survey-foot definition applies. This everyday converter uses the international foot of exactly 0.3048 meter.
Related tools and next steps
Area Converter, Volume Converter, Weight Converter, Speed Converter, Converters
Common questions this tool can help answer
Common length questions this converter can help answer
- How many inches are in a centimeter?
- How do I convert feet and inches to centimeters?
- What is a kilometer in miles?
- What is the difference between a statute mile and a nautical mile?
- How do metric prefixes change a meter?
- Which length conversion factors are exact?
Sources and methodology
The formulas, standards, and reference information on this page are checked against the authoritative sources below. External references open the original source.
- NIST: SI units of length
- NIST Guide to the SI: Exact conversion factors
- NIST Guide to the SI: Units outside the SI
- NIST: Writing with SI metric units and prefixes
Frequently asked questions
Which length units are supported?
The converter supports nanometers, micrometers, millimeters, centimeters, meters, kilometers, international inches, feet, yards, statute miles, and international nautical miles.
Are the conversion factors exact?
The metric powers of ten and the international definitions used here are exact: 1 inch = 0.0254 meter, 1 foot = 0.3048 meter, 1 yard = 0.9144 meter, 1 statute mile = 1,609.344 meters, and 1 international nautical mile = 1,852 meters.
How do I convert feet and inches to centimeters?
Choose Feet and inches mode, enter each part separately, and select centimeters. Mathematically, multiply the feet by 12, add the remaining inches, then multiply the total inches by exactly 2.54 centimeters.
How many centimeters are in one inch?
One international inch equals exactly 2.54 centimeters. Therefore, divide centimeters by 2.54 to find inches or multiply inches by 2.54 to find centimeters.
How many feet are in one meter?
One meter is approximately 3.28084 international feet. The displayed value is rounded because the exact relationship is defined in the other direction: one international foot equals exactly 0.3048 meter.
What is the difference between a statute mile and a nautical mile?
A statute mile equals exactly 1,609.344 meters and is commonly used for land distance. An international nautical mile equals exactly 1,852 meters and is used in marine and aviation navigation.
What do nm and µm mean?
nm means nanometer, which is 10⁻⁹ meter. µm means micrometer, which is 10⁻⁶ meter. The Greek letter µ is the SI symbol for the prefix micro.
Why does the answer change when I adjust decimal places?
Only the displayed rounding changes. The converter continues using the full numeric conversion factor internally, so increase the decimal setting when the result will feed another calculation.
Can I convert a negative length?
Standard mode accepts signed values because negative differences and coordinates can be mathematically meaningful. A physical object's length or a traveled distance is normally entered as a nonnegative value.
Does this use the U.S. survey foot?
No. It uses the international foot of exactly 0.3048 meter. Historical land and surveying records may use a different survey-foot definition, so verify the governing standard for specialist work.
Can converted digits be more accurate than the original measurement?
No. A mathematically exact conversion can still begin with a rounded or uncertain measurement. Keep appropriate significant figures for scientific, engineering, surveying, manufacturing, or compliance work.
https://wowwebtools.com/converters/length-converter