Length Converter

1. Enter the value you want to convert.
2. Choose the unit you have and the unit you want from the dropdowns.
3. Read the converted value, the conversion factor and the value in metres, all updating live.

Each output helps in a different way:

A length conversion expresses the same distance in a different unit. The distance itself never changes; only the number and the label do. A run of 5 kilometres is exactly the same as 3.107 miles, just measured on a different ruler.

The world uses two main systems. The metric system, based on the metre, scales in powers of ten, so a kilometre is 1,000 metres and a centimetre is a hundredth of one. The imperial and US customary system uses inches, feet, yards and miles, which relate by 12, 3 and 1,760. Converting between the two is the everyday job of a length converter.

Every unit is defined as a fixed number of metres, so the converter turns your value into metres, then into the unit you want.

For example, one foot is defined as exactly 0.3048 metres and one inch as 0.0254 metres. To convert feet to inches, the tool multiplies by 0.3048 to reach metres, then divides by 0.0254, giving the familiar 12 inches per foot. Using metres as a common base keeps every conversion consistent and exact.

1. Multiply the value by the metres in one source unit.
2. Divide by the metres in one target unit.
3. The result is your length in the unit you wanted.

Because the factors are the internationally agreed definitions, the results match official conversions to the last place.

Convert 100 metres to feet. One metre is 3.28084 feet, so 100 metres is 100 x 3.28084 = 328.084 feet. The same 100 metres is 0.06214 miles or 10,000 centimetres.

Now convert a marathon of 26.2 miles to kilometres. One mile is 1.609344 kilometres, so 26.2 x 1.609344 = 42.16 kilometres, the familiar marathon distance. The converter reaches this by turning miles into metres and metres into kilometres in one step.

Convert 12 inches to feet and the answer is exactly 1, confirming the definition that twelve inches make a foot.

These are the everyday units and how they relate to the metre, the international base.

A yard and a metre are close but not equal, which is a common source of small errors in sport and construction.

The distance is fixed, but a couple of things affect the number you read.

The Units You Pick

Choosing the wrong source or target unit is the biggest cause of a wrong answer, so check both dropdowns.

Rounding

Many conversions are not exact decimals, so a rounded figure differs slightly from the full value; this tool keeps six places.

US Versus Imperial Subtleties

For everyday lengths the US and imperial foot are identical, but a few historical survey units differ by a tiny amount.

Very Large or Small Values

Extreme values are handled, but rounding matters more at the far ends of the scale.

Travel and Sport

Turn miles into kilometres for a road sign or a race, or a height in feet into metres.

DIY and Construction

Convert plans and materials between metric and imperial so measurements line up on site.

Study and Science

Move between units for homework or lab work, keeping every figure on the same scale.

1. Swapping the from and to Units

Converting the wrong way inverts the result. Check that the source and target are the right way round.

2. Confusing a Yard with a Metre

They are close but a yard is 0.9144 metres, so treating them as equal introduces an error.

3. Mixing Up Centimetres and Millimetres

A centimetre is ten millimetres; slipping a factor of ten is easy and costly.

4. Rounding Too Early

Round only the final answer, not the intermediate metres, to keep the result accurate.

5. Assuming 1 Mile Is 1.6 Km Exactly

It is 1.609344 kilometres; the rounded 1.6 is fine for a quick guess but not for precision.

The converter uses the exact international unit definitions, so results are accurate to the places shown.

Multiply the metres by 3.28084. So 100 metres is 328.084 feet. This converter does it instantly when you pick metres and feet.

One mile is 1.609344 kilometres. To convert miles to kilometres, multiply by 1.609344; to go the other way, divide by it.

Multiply the inches by 2.54, since one inch is exactly 2.54 centimetres. Ten inches is 25.4 centimetres.

The metre is the international base unit. Every other length unit is defined as a fixed number of metres, which is how this converter links them all.

No, but they are close. A yard is 0.9144 metres, about 8.6 percent shorter, so they should not be treated as equal in precise work.

There are 5,280 feet in a mile. A mile is 1,760 yards, and each yard is 3 feet, which multiplies to 5,280.

Divide the centimetres by 2.54. So 25.4 centimetres is 10 inches. The converter handles it when you choose the two units.

No. This tool converts length only. Area uses squared units and volume uses cubed units, which follow different factors.

No. The calculation runs in your browser, and nothing you enter is sent anywhere unless you Save a result, which stays on this device only.

• Unit of length (Wikipedia).
• Metric length (Maths Is Fun).
• Conversion of units (Wikipedia).