How to use the Length Converter
- Type a number in the Value box and choose the unit in From. Example: 32 inches.
- Choose a unit in To. The result appears in large text at the top, and the table below shows the value in every unit.
- Use a Copy button in the table to copy the value you need.
- To check a TV or monitor size, enter the size in inches and the aspect ratio below to see the actual width and height of the screen.
How many cm in an inch? Length conversion chart
The inch, foot, yard and mile were defined in meters by the 1959 international yard and pound agreement, so their metric values are exact and never change.
| Unit | Metric equivalent | Relationship |
|---|---|---|
| 1 inch (in) | 2.54 cm | - |
| 1 foot (ft) | 30.48 cm | 12 inches |
| 1 yard (yd) | 91.44 cm | 3 feet |
| 1 mile (mi) | 1.609344 km | 1,760 yards |
| 1 nautical mile (nmi) | 1.852 km | Used at sea and in aviation |
Going the other way, 1 cm is about 0.3937 inches, 1 m is about 3.2808 feet (or 1.0936 yards), and 1 km is about 0.6214 miles.
The US officially retired the old "US survey foot" at the end of 2022, so the international foot of exactly 0.3048 m is now the standard everywhere.
Height in feet to cm: how tall is 5 ft 9 in?
In the US and the UK, height is usually written in feet and inches, like 5'9". To convert, multiply the feet by 30.48, multiply the inches by 2.54, and add the two.
- 5 ft 9 in = 5 × 30.48 + 9 × 2.54 = 152.4 + 22.86 = 175.26 cm
- 6 ft = 6 × 30.48 = 182.88 cm
- 170 cm = 170 ÷ 2.54 ≈ 66.93 inches = 5 ft about 6.9 in
To turn centimeters into feet and inches, divide by 2.54 to get total inches, then divide by 12: the whole number is feet and the remainder is inches.
Pants (trouser) waist sizes are also in inches. A 30-inch waist is 30 × 2.54 = 76.2 cm, and a 32-inch waist is 81.28 cm.
How to calculate TV and monitor size
A screen size in inches is the diagonal, not the width. You can find the width and height from the aspect ratio using the Pythagorean theorem. For a 16:9 screen, the diagonal ratio is √(16² + 9²) ≈ 18.36, so width = diagonal × 16 / 18.36 and height = diagonal × 9 / 18.36.
| Size (16:9) | Diagonal | Width × height (approx.) |
|---|---|---|
| 24 in | 60.96 cm | 53.1 × 29.9 cm (20.9 × 11.8 in) |
| 27 in | 68.58 cm | 59.8 × 33.6 cm (23.5 × 13.2 in) |
| 32 in | 81.28 cm | 70.8 × 39.8 cm (27.9 × 15.7 in) |
| 55 in | 139.7 cm | 121.8 × 68.5 cm (47.9 × 27.0 in) |
| 65 in | 165.1 cm | 143.9 × 80.9 cm (56.7 × 31.9 in) |
The actual product is a little larger because of the bezel and stand. When measuring a TV cabinet or wall space, also check the overall dimensions on the manufacturer's spec sheet.
Where imperial and metric units are used
The US uses inches, feet, yards and miles for most everyday measurements. The UK is mostly metric but still uses miles and yards on road signs, and feet and inches for height. Canada and Australia are officially metric, though people often still give height in feet and inches and TV sizes in inches everywhere.
- Road distances: miles in the US and UK, kilometers in Canada and Australia.
- Building and DIY: feet and inches in the US; millimeters on Australian and UK plans.
- Sea and air: nautical miles worldwide.
Traditional Korean units: ja, chi and gan
The converter also includes traditional Korean length units, which you may see in older Korean documents or property listings. The ja (similar to a foot) was standardized in modern times as 10/33 m, about 30.3 cm. One ja equals 10 chi, and 6 ja make 1 gan (about 1.818 m). The Korean area unit pyeong is a square of 1 gan × 1 gan, which is why 1 pyeong is about 3.3058 m². For area conversions, use the pyeong calculator.