Length & Distance Converter

Convert between commonly used unit pairs such as cm ⇄ inch and feet ⇄ meter.

Use this converter to switch between length and distance units. Select the current unit in the left column, the desired unit in the right column, and enter a value to see the resulting conversion instantly.

Converting length units (metric and imperial).

Type a value, pick the units on both sides, and the result updates automatically.

1 meter (m) = 0.001 kilometer (km)
  • Reverse conversion: 1 kilometer (km) = 1000 meter (m)
  • Use this line as a quick reference for similar values.

Understanding length and distance conversions

A length and distance converter is a simple but powerful tool that turns one measurement unit into another. When you type a value and pick a pair of units (for example cm to inch or meter to feet), the calculator multiplies your value by a precise conversion factor. This lets you move back and forth between the metric system and imperial units without having to remember every formula.

The general idea is always the same: value in target unit = value in source unit × conversion factor. As long as the factor is correct and you choose the right units on each side, your result will be accurate every time.

Metric length units at a glance

The metric system is based on powers of ten, which makes conversions inside the system very easy. All metric length units are related to the meter:

  • Millimeter (mm) – one thousandth of a meter (0.001 m).
  • Centimeter (cm) – one hundredth of a meter (0.01 m).
  • Meter (m) – the base unit for distance in the SI system.
  • Kilometer (km) – one thousand meters (1000 m).

Because every step is a factor of 10, you can often convert between metric units just by moving the decimal point. For example, 1.5 m = 150 cm and 0.02 km = 20 m.

Imperial and US customary units

Imperial and US customary units were developed historically and are not based on powers of ten. This makes a converter especially useful when you need to switch between inch, foot, yard and mile. Some of the most important relationships are:

  • 12 inches (in) = 1 foot (ft)
  • 3 feet = 1 yard (yd)
  • 1760 yards = 1 mile (mi)

When converting between metric and imperial units, the tool uses fixed factors, such as 1 inch = 2.54 cm and 1 mile = 1.609344 km. This is more reliable than rounding everything in your head.

Common length conversion examples

Here are a few everyday examples of conversions that this calculator can perform instantly:

  • cm ⇄ inch – useful for clothing sizes, device dimensions and small objects.
  • meter ⇄ feet – often used for room height, furniture and building plans.
  • kilometer ⇄ mile – helpful for running distances, road trips and maps.
  • millimeter ⇄ inch – handy for engineering drawings and hardware sizing.

When a length converter is especially useful

A distance converter is helpful in many situations:

  • Study and homework – checking answers for physics and math problems.
  • DIY and construction – reading blueprints or tool measurements that use a different unit system than you are used to.
  • Travel and navigation – understanding road signs, map scales and running routes that use miles or kilometers.
  • Shopping online – comparing product sizes when stores list dimensions in different units.

Tips for accurate conversions

  • Always double-check that the left side (“From”) matches the unit of your original value.
  • Use the swap button after converting if you want to quickly reverse the direction.
  • For printed work or reports, keep at least two–four decimal places for precise results.
  • For quick mental estimates, remember a few anchor values such as 1 in ≈ 2.54 cm and 1 ft ≈ 0.3048 m.

Brief history of length measurement

Early units of length were based on everyday objects: the length of a forearm, the span of a hand or the distance a person could walk in a set time. As trade and science developed, these rough measures were replaced by more stable definitions so that builders, merchants and scientists could all work with the same standards.

The modern International System of Units (SI) defines the meter using the speed of light in vacuum, which is a constant of nature. This extremely precise definition ensures that conversions between metric and non-metric units are consistent in laboratories, industries and everyday tools like this one.

FAQ: length and distance conversion

Is this length converter accurate enough for professional work?
Yes. The tool uses official conversion factors (for example 1 inch = 2.54 cm exactly), which are the same values used in engineering handbooks and scientific references.

Do I need an internet connection for the calculations?
No. All calculations happen in your browser with JavaScript. After the page has loaded, the converter can work even if your connection is slow or temporarily offline.

Can I use the results in reports or homework?
Absolutely. Enter your original value, choose the units, and then copy the converted result. For formal documents, it is a good idea to round to a sensible number of decimal places based on how precise your original measurement was.