Length converter
Convert metres, kilometres, centimetres, inches, feet, yards, miles and nautical miles.
Your inputs
Your results
Ready when you areYour results will appear here.
How it works
Convert a length between metric units, international inch-based units and nautical miles. Enter a single numeric length, choose its source and destination, and inspect the equivalent values in all supported units.
A few things to know
Nonnegative lengths only. Feet and miles use international definitions, not historical U.S. survey units. Does not parse mixed feet-and-inches expressions, determine measurement uncertainty, or convert map coordinates. Display uses up to 12 significant digits; this is not arbitrary-precision arithmetic or a measurement calibration. Numeric magnitude is bounded to 1e100, with nonzero inputs at least 1e-100.
When to use this tool
A length conversion changes the unit used to describe a distance without changing the distance itself. This converter handles metric lengths, international inch-based measurements and nautical miles in one place. Enter a decimal value, select its starting unit and choose the unit you need. The result includes an equivalent-value table and CSV export, so a specification can be checked across several systems. Feet and miles use international definitions; older survey-based measurements need their own documented conversion.
- Compare dimensions from a product listing that uses inches with a metric specification.
- Translate a distance recorded in miles or nautical miles into kilometers.
- Prepare a reference table of one measured length in units used by different teams.
How to use length converter
Enter one numeric length
Put the measured number in Value. Use a decimal or scientific notation, without unit letters or mixed feet-and-inches notation.
Identify its source unit
Choose From unit, paying attention to international feet, international miles and nautical miles. A number alone does not identify which distance unit was intended.
Choose and read the target
Set To unit and calculate. Read Converted value, review the full table for other equivalents and download the CSV if useful.
Twelve inches in centimeters
Inputs
Value 12; From unit Inches (in); To unit Centimeters (cm).
Result
Converted value is 30.48 centimeters. The same table includes 0.3048 meters and 1 international foot.
What it means
The input represents one distance described with several units. Each inch corresponds to 2.54 centimeters, so twelve inches gives 12 × 2.54 = 30.48; there is no change to the object’s actual size.
Common mistakes to avoid
Entering 5.8 for five feet eight inches
Decimal feet and feet-plus-inches are different. Five feet eight inches is 5 + 8/12 feet, not 5.8 feet.
Using the wrong mile
A nautical mile and an international mile have different lengths. Select the unit written in the original source.
Overstating measurement precision
A detailed conversion does not improve the accuracy of a roughly measured dimension. Retain a sensible precision for the original measurement.
Frequently asked questions
Definitions, edge cases, and practical next steps for this tool. Search all tool FAQs ↗
How does the length conversion work?
The tool expresses the source unit in meters, multiplies by the entered value, then divides by the destination unit’s meter factor. Metric prefixes and international inch-based definitions provide the factors. The same approach creates every row in the table.
Is an inch exactly 2.54 centimeters?
Yes, under the international inch definition used here. The corresponding international foot is 0.3048 meter and yard is 0.9144 meter. Exact definitions do not mean every decimal output or original measurement has unlimited numeric precision.
Does this support the old U.S. survey foot?
No. The foot option is explicitly the international foot. Historical survey documents can use a different foot definition. Check the original document’s basis rather than applying this converter to a legacy coordinate or cadastral measurement without that verification.
Can I enter feet and inches together?
The Value field accepts a single numeric quantity, not expressions such as 5 ft 8 in. Convert the inches to a fraction of a foot first, or enter the complete distance in inches and choose inches as the source.
What is the difference between a mile and a nautical mile?
The mile option uses 1,609.344 meters. A nautical mile uses 1,852 meters. They are separate choices because substituting one for the other changes the result. The converter does not infer a nautical unit from context or location.
Can lengths be zero or negative?
Zero is supported and produces zero in every unit. Negative lengths are rejected because this tool treats input as a length magnitude. It does not convert signed displacement coordinates or interpret direction along an axis.
Can I enter very small dimensions?
Yes, including micrometers or scientific notation such as 1e-6 meters. Supported nonzero inputs have magnitude at least 1e-100 and at most 1e100. Results may use scientific notation and display up to 12 significant digits.
Does the table calculate area or volume?
No. Every row describes the same linear length. Square and cubic unit factors are different. Use the area converter for a measured area or the volume converter for a volume instead of applying a length ratio directly.
Explore the topic in the blog
Sources and method
Use the references below to check definitions and platform guidance. The model’s scope and limits are explained above. Read our editorial standards.