Length Universal Converter
Convert a length or distance between meters, centimeters, millimeters, kilometers, inches, feet, yards, miles, and nautical miles. Enter a value, then choose the From unit and To unit.
Universal Length & Distance Converter
Length Conversion Formula
Where:
- \(V_{\mathrm{from}}\) — the length entered in the From unit.
- \(V_{\mathrm{to}}\) — the converted length in the To unit.
- \(F_{\mathrm{from}}\) — the number of From units per meter.
- \(F_{\mathrm{to}}\) — the number of To units per meter.
The calculator first divides by the source unit’s units-per-meter factor to obtain meters. It then multiplies by the target unit’s factor to produce the converted length.
Length Conversion – Calculation Example
Example: Convert the default value of 1 meter to feet. The calculator uses 1 meter per meter and 3.28084 feet per meter.
\[ V_{\mathrm{to}}=1\,\mathrm{m}\times\frac{3.28084\,\mathrm{ft/m}}{1\,\mathrm{m/m}}=3.28084\,\mathrm{ft} \]
Result: 1 meter is displayed as 3.28084 feet.
How to use the calculator
- Enter a nonnegative number in Length value. Use the amount you want to convert, such as 2.5 for a length of 2.5 units.
- Choose the unit of that number in From unit.
- Choose the unit you want in To unit.
- Read Converted Length. The number is followed by the selected target unit.
For example, to convert a measurement taken in inches to centimeters, enter the measured number, set From unit to Inch (in), and set To unit to Centimeter (cm). You can select the same unit in both menus to leave the value unchanged. For a dedicated version of the default conversion, see the meters to feet calculator.
What length conversion means
Length conversion expresses the same physical distance in a different unit. A number changes when its unit changes, but the distance does not: 1 meter and approximately 3.28084 feet describe the same length. This is useful when a drawing, product specification, route, or measurement uses units different from the ones you need.
The available metric units are millimeters, centimeters, meters, and kilometers. The calculator also includes inches, feet, yards, miles, and nautical miles. Nautical miles are commonly used for marine and air navigation; they are not the same length as ordinary miles. Check the unit abbreviation next to the result when working with mi and nm.
Every conversion passes through meters. For instance, converting feet to kilometers means first expressing the entered feet as meters and then expressing those meters as kilometers. This method allows the same formula to handle any pair of units in the menus. A length is a one-dimensional measurement, so this result should not be used as an area conversion. If you need to convert the size of a plot rather than the length of one side, use the land area unit converter.
Conversion factors used
The factors below are the numbers of each unit in one meter. They are the values used by this calculator, including its rounded factors for some nonmetric units:
- Metric: 1 m, 100 cm, 1,000 mm, or 0.001 km per meter.
- Inches, feet, and yards: 39.3701 in, 3.28084 ft, or 1.09361 yd per meter.
- Longer distances: 0.000621371 mi or 0.000539957 nm per meter.
These are units per meter, not meters per unit. To convert from a unit to meters, divide the entered value by its listed factor. To convert from meters to a unit, multiply by that factor. For metric-scale conversions involving other prefixes, the metric prefix converter may also be useful.
Assumptions and practical tips
The calculator displays the result rounded to six decimal places. Its factors for inches, feet, yards, miles, and nautical miles are also rounded, so a converted value may differ slightly from one calculated using full-precision definitions. If you are checking a technical specification or need a regulated level of precision, use the specified conversion standard and retain sufficient digits throughout the calculation.
Very small results can display as zero after rounding even though the unrounded length is greater than zero. In that case, try a smaller target unit: for example, choose millimeters instead of kilometers. The field accepts nonnegative values, so it is suited to lengths and distances rather than signed positions or displacements.
Frequently Asked Questions
How do I convert feet and inches to centimeters?
Turn the measurement into inches first: multiply the feet by 12, then add the remaining inches. For example, 5 feet 7 inches is 67 inches. Multiply by 2.54 to get 170.18 centimeters. The converter accepts one unit at a time, so enter 67 with inches as the starting unit rather than entering “5 feet 7 inches.”
How many centimeters are in an inch?
One inch is exactly 2.54 centimeters. To convert inches to centimeters by hand, multiply by 2.54; to convert centimeters to inches, divide by 2.54. For example, 8 inches equals 20.32 centimeters. The calculator uses a rounded inches-per-meter factor, so its displayed answer can differ slightly from a calculation using the exact definition.
How do I convert miles to kilometers without a calculator?
Multiply ordinary miles by approximately 1.609 to get kilometers. For a quick estimate, multiply by 1.6: 10 miles is about 16 kilometers. For a more precise hand calculation, one international mile is exactly 1.609344 kilometers. To go the other way, divide kilometers by 1.609344, or multiply by approximately 0.6214.
Is a nautical mile the same as a regular mile?
No. A nautical mile is exactly 1,852 meters, while an international mile is exactly 1,609.344 meters. One nautical mile is therefore about 1.151 ordinary miles. Nautical miles are used in marine and air navigation; ordinary miles are commonly used for road distances. Check which type of mile your source uses before converting.
Why might converting a length back to its original unit give a slightly different number?
Small differences can come from rounding, not a change in the underlying distance. This calculator uses rounded factors for several nonmetric units and displays results to six decimal places. If you copy a displayed result into a second conversion, you also carry forward that display rounding. For precision-sensitive work, keep more digits during intermediate calculations and use the required conversion standard.
Can I use a length conversion factor for area or volume?
Not without adjusting the factor. Area has two dimensions, so you square the length conversion factor; volume has three, so you cube it. Because 1 foot equals 12 inches, 1 square foot equals 144 square inches, and 1 cubic foot equals 1,728 cubic inches. Entering an area or volume directly into a length converter would give an incorrect result.