Contents
- ๐ What is this?
- ๐จ๐ปโ๐ป How to use it?
- ๐ฐ Examples
- ๐ Nuances
- ๐ค Frequently asked questions
- ๐ Related materials
Convert a length in either direction
Enter a measurement in either field and choose its unit. The paired field updates immediately, so the same form converts metric and imperial lengths without a separate calculation step.
Choose the units before judging the number
The converter supports millimetres, centimetres, metres, kilometres, inches, feet, yards, and statute miles. You can edit either side or use the swap control when you want to reverse the pair.
Each factor k expresses one unit in metres. The source value is first converted to metres and then divided by the target factor. NIST records the international inch as exactly 25.4 mm, which also fixes the international foot, yard, and mile.
Three conversions worth recognising
A doorway. A width of 36 inches equals 91.44 centimetres. That is exact before display rounding because 1 inch equals 2.54 cm.
A room. A 4.5 metre wall is about 14.76378 feet. For buying material, round only after applying any cutting allowance required by the project.
A road distance. 10 miles equals 16.09344 kilometres. The calculator uses the international statute mile, not the nautical mile used in navigation.
Displayed precision is not measurement precision
The result shows at most six decimal places. A long repeating conversion may therefore display a rounded value even though the stored factors remain unchanged.
Keep only as many meaningful digits as the original measurement supports. A board measured to the nearest centimetre does not become micrometre-accurate after conversion. This tool also does not convert square or cubic units, because area and volume use squared or cubed factors.
Questions about length conversion
Most mistakes come from choosing a similar-looking but different unit or rounding too early.
How do I reverse a conversion?
Edit the other number field or press the swap control. The units and values exchange sides while preserving the same physical length.
Is one inch exactly 2.54 centimetres?
Yes. The international inch is defined as exactly 25.4 millimetres, which is 2.54 centimetres.
Can I enter decimal measurements?
Yes. Both number fields accept decimal values, and either field can drive the conversion.
Does mile mean nautical mile?
No. The converter uses the international statute mile of 1,609.344 metres. A nautical mile is 1,852 metres and is not included here.
Why are some results rounded?
The interface shows up to six decimal places to keep long results readable. Round further only when your real measurement or task requires it.
Similar calculators
You may find the following calculators on the same topic useful:
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- Circle Diameter Calculator. Calculate the diameter of a circle based on the circumference, radius, or area of the circle.
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- Parallelepiped Volume. Calculate the volume of any parallelepiped online based on the lengths of its edges and more.
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- Triangle Area Calculator. Determine the area of a triangle online using different methods (angles, sides, height).
- Cylinder Volume Calculator. Determine the volume of cylindrical shapes: from pipes to cans in different units of measurement.
- Cone Volume Calculator. Calculate the volume of various conical forms in cubic meters or liters.
- Truncated Pyramid Volume Calculator. Determine the volume of a truncated pyramid based on its height and base areas.
- Cylinder Surface Area Calculator. Determine the surface area of any cylindrical element.
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