Length Converter
Convert between length units: millimetres, centimetres, metres, kilometres, inches, feet, yards, and miles.
Ready to calculate?
› Open the Unit ConverterBackground
Length measurement is one of the oldest and most fundamental types of quantification. The metric system is the international standard; the imperial system remains common in the US.
Metric vs Imperial Systems
The metric system is decimal-based — each unit is 10, 100, or 1000 times the next. Imperial units have irregular ratios (12 inches per foot, 3 feet per yard), making manual conversion error-prone.
The 1959 International Agreement
In 1959, English-speaking nations standardised the inch at exactly 25.4 mm. Before this, the US and British inches differed slightly.
How to Use This Calculator
- Select 'Length' from the category dropdown
Open the Unit Converter and choose Length.
- Select your source unit
Choose mm, cm, m, km, in, ft, yd, or mi.
- Enter the value
Type the number you want to convert.
- Select your target unit
Choose the unit to convert to.
- Read the result
The converted value appears instantly with full precision.
Applications
Common Conversions
Some common conversions using our length converter include converting a room's dimensions from square feet to square meters for a remodel, or converting the length of a football field from yards to meters for a race.
Converting for Architecture
Our length converter tool can be especially useful for architects and designers who need to work with different units of measurement when creating blueprints and designs. For example, you may need to convert the distance between two points in feet to meters for a European client, or convert the area of a room in square feet to square meters for a project in Japan.
Real-World Examples
Our length converter has been used by architects to measure the dimensions of buildings, by interior designers to calculate room sizes, and by construction workers to measure the length of materials on a job site. It's also useful for students studying different units of measurement in math class.
Real World Examples
For example, if you want to know how many square feet of carpet you need for a room that measures 12 feet by 15 feet, you can use our tool to convert the length and width to meters. Then, you can multiply the meter measurement by the conversion factor for square meters to get the total area in square meters. Finally, you can convert the square meters back to square feet using the reverse conversion factor.
Frequently Asked Questions
How do you convert inches to millimetres?
Multiply inches by 25.4. For example, 5 in × 25.4 = 127 mm. This is exact.
How do you convert metres to feet?
Multiply metres by 3.28084. For example, 2 m = 6.56 ft.
How do you convert km to miles?
Multiply km by 0.621371. For example, 100 km = 62.14 miles.
How do you convert square feet to square meters?
To convert square feet to square meters, multiply the square foot value by 0.11 (since there are 11 square meters in a square foot).
How do you convert yards to meters?
To convert yards to meters, divide the yard value by 0.91 (since there are 0.91 meters in a yard).
How do you convert a mixture of units?
Our length converter tool allows you to mix and match different units, simply enter the values in the appropriate fields.
Can I convert units that are not listed on the tool?
Sorry, our tool currently only supports the most common units of measurement. If you need to convert a unit that is not listed, please let us know and we may be able to add it in the future.
How do I convert a mixture of units?
Our tool allows you to convert a mixture of units by selecting the desired conversion type and entering the values in the appropriate fields. For example, you can convert 10 inches and 5 feet to meters by selecting 'Other' as the conversion type and entering 10/3 = 3.33 for the first value and 5/3 = 1.67 for the second value.