How many centimeters are in an inch?
One inch is exactly 2.54 centimeters. The value was fixed by international agreement in 1959, which makes converting simple:
inches = cm ÷ 2.54 · cm = inches × 2.54
A foot is 12 inches, or 30.48 cm. In the United States and the United Kingdom people's height is usually given in feet and inches, such as 5′ 10″ (5 feet 10 inches). The single prime ′ stands for feet and the double prime ″ for inches.
Examples
- 180 cm to inches: 180 ÷ 2.54 = 70.87 inches. That is 5 feet (60 inches) plus 10.87 inches, which rounds to 5′ 10⅞″ at the nearest eighth of an inch.
- 65 inches to cm: 65 × 2.54 = 165.1 cm.
- 5′ 10″ to cm: (5 × 12 + 10) × 2.54 = 70 × 2.54 = 177.8 cm.
- A 55-inch TV: the screen diagonal is 55 × 2.54 = 139.7 cm. On a 16:9 screen the picture is about 122 cm wide and 68.5 cm high.
Height chart: cm to feet and inches
| Height | Inches | Feet and inches |
|---|---|---|
| 150 cm | 59.1 | 4′ 11″ |
| 160 cm | 63.0 | 5′ 3″ |
| 165 cm | 65.0 | 5′ 5″ |
| 170 cm | 66.9 | 5′ 6⅞″ |
| 175 cm | 68.9 | 5′ 8⅞″ |
| 180 cm | 70.9 | 5′ 10⅞″ |
| 185 cm | 72.8 | 6′ 0⅞″ |
| 190 cm | 74.8 | 6′ 2¾″ |
| 200 cm | 78.7 | 6′ 6¾″ |
Where inches show up
Even in metric countries inches are everywhere:
- Screens and phones: screen sizes are the diagonal in inches. A 15.6-inch laptop has a 39.6 cm diagonal.
- Bikes and tires: a 29-inch mountain bike wheel and a car tire marked "R17" (a 17-inch rim) are inch sizes.
- Jeans: W32 L34 means a 32-inch (81 cm) waist and a 34-inch (86 cm) inside leg.
- Pipes and fittings: sizes such as ½″ and ¾″ are standard, although the actual outside diameter often differs from the name.
- Lumber: a US "2×4" is nominally 2 by 4 inches, but actually 1½ by 3½ inches (38 × 89 mm) after drying and planing.
Mental math shortcuts
- cm to inches: divide by 2.5 and take off 2%. 100 cm ÷ 2.5 = 40, minus 2% ≈ 39.2 (exact: 39.37).
- inches to cm: multiply by 2.5 and add 2%. 20 in × 2.5 = 50, plus 1 = 51 cm (exact: 50.8).
- feet to cm: about 30 cm per foot; 6 feet is about 1.83 m.
For other lengths such as miles and yards, use the unit converter. To convert body weight, use kg to lbs.
Why are there inches and centimeters?
The inch is an old unit that existed in many countries, each with a slightly different length. Since 1959 the international inch has been exactly 2.54 cm everywhere, so there is no longer any confusion between countries. The United States still uses inches, feet and yards for everyday measurements, and the UK uses them informally for height, distance and some products. Even in metric countries you meet inches daily: screens, TVs, bicycle wheels, car rims, jeans, pipes and tools are often sized in inches. Science, medicine and most international trade use the metric system. The calculator converts in both directions, including feet and inches together, so you can switch between the two systems without mental arithmetic.
Frequently asked questions
How many cm is 1 inch?
Exactly 2.54 cm. The other way round, 1 cm is about 0.3937 inches.
How tall is 6 feet in cm?
6 × 30.48 = 182.88 cm, or about 1.83 meters.
How big is a 65-inch TV in cm?
The diagonal is 65 × 2.54 = 165.1 cm. On a 16:9 screen the width and height are about 144 cm and 81 cm.
What do ′ and ″ mean?
The single prime ′ means feet and the double prime ″ means inches. 5′ 9″ is 5 feet 9 inches, or 175.3 cm.
Why round to an eighth of an inch?
Inch measurements are usually written as fractions: ½, ¼ or ⅛ inch. An eighth of an inch is about 3 mm. The decimal value is shown as well.
How do I convert my height for a form?
Enter your height in cm and read the feet-and-inches line. Most forms ask for whole inches, so 5′ 10⅞″ becomes 5′ 11″.
Last reviewed: 2026-10-06. Results are estimates for information only.