Transparent method
The formula
Worked example
Example inputs
How to interpret the result
Every conversion factor here is an internationally defined constant, not a rounded approximation, so the arithmetic itself carries no error at all. Any mismatch between a converted figure and a real-world measurement comes from the original measurement, not from anything this calculator does with it. Reference values: an inch is exactly 25.4 millimeters, a foot is 0.3048 meters, a mile is 5,280 feet or 1,609.344 meters, and a nautical mile is 1,852 meters. A kilometer is about 0.621 miles, and a yard is 0.9144 meters.
Before you rely on it
What to check
Confirm which unit you're converting from and to before reading the result, especially between metric and imperial systems where a mixed-up direction produces a plausible-looking but wrong figure.
The common error
Where people go wrong with length converter calculator
Swapping the from-unit and to-unit by mistake. The math runs correctly either way, so a reversed conversion still produces a clean-looking number that's simply answering the opposite question.
Sensitivity evidence
How value changes the converted value
| Value | Converted value | 1 unit of "to" in "from" units |
|---|---|---|
| 8 | 2.4 | 3.3 |
| 9 | 2.7 | 3.3 |
| 10worked example | 3 | 3.3 |
| 11 | 3.4 | 3.3 |
| 12 | 3.7 | 3.3 |
Every input, tested
Which input moves the converted value most
| Input | Tested from | To | Converted value at each end | Swing |
|---|---|---|---|---|
| From | Millimeters | Nautical miles | 0.01 to 18,520 | 18,520 (328084%) |
| To | Millimeters | Nautical miles | 3,048 to 0.00165 | 3,048 (100000%) |
| Value | 9 | 11 | 2.7 to 3.4 | 0.61 (20%) |
Step by step
The worked example, input by input
| Input | Value used | What it means |
|---|---|---|
| Value | 10 | |
| From | Feet | Unit to convert from. |
| To | Meters | Unit to convert to. |
| Converted value | 3 | |
| 1 unit of "to" in "from" units | 3.3 | |
Inputs, definitions and assumptions
Value
From
Unit to convert from.
To
Unit to convert to.
Where the inputs come from
Enter the value and choose the unit you are converting from and to: millimeters, centimeters, meters, kilometers, inches, feet, yards or miles. Read the measurement from a tape, a plan or a map scale, and keep the unit it was measured in. All conversions pass through meters, using exact definitions such as 1 inch equals 25.4 millimeters and 1 foot equals 0.3048 meters. Do not round the input before converting.
When the result stops applying
Nautical miles and surveyor's feet are different units from the ones listed. Fractions of an inch need decimal conversion first. Very small or very large values may be better expressed in scientific notation. Surveying uses the US survey foot, which differs from the international foot by about two parts per million and matters only over long distances. A nautical mile is exactly 1,852 meters, which is not the same as a statute mile of 1,609.344 meters.
What to compare it with
Convert areas on the area converter, volumes on the volume converter, and heights in feet and inches on the height converter. The scientific notation page handles very large or small values, and the rectangle and circle area calculators use lengths. The speed converter combines length and time units.
People also ask
Frequently asked questions
How many centimeters are in an inch?
Exactly 2.54 centimeters, which is the international definition used for all inch and metric conversions.
How do I convert feet to meters?
Multiply the number of feet by 0.3048. Ten feet is 3.048 meters.
Is a nautical mile the same as a mile?
No. A nautical mile is 1,852 meters, about 1.15 statute miles, and is used in sea and air navigation.