Inches to Centimeters: Formula, TV Sizes and Quick Chart
Convert inches to cm with the exact 1 in = 2.54 cm formula, a quick chart, height in feet and inches, and the real width and height of 16:9 TV screens.
Inches show up in a lot of places, even in countries that use the metric system. TV and monitor sizes, phone screens, picture frames, bike wheels and American recipes or product listings often use inches. If you think in centimeters, you need a quick way to turn one into the other.
This guide covers the exact conversion and the formulas in both directions. It also includes a ready-made chart, a way to convert height given in feet and inches, and a method for finding the real width and height of a TV from its advertised size. All numbers are rounded to one decimal place.
The exact rule: 1 inch = 2.54 cm
The inch has been officially defined as exactly 2.54 centimeters since an international agreement in 1959. “Exactly” means the number is not rounded. If you multiply by 2.54, your answer is as accurate as your input.
The two formulas you need are:
- Inches to centimeters: cm = inches × 2.54
- Centimeters to inches: inches = cm ÷ 2.54
For centimeters to inches, you can also multiply by about 0.3937. That number is rounded, so dividing by 2.54 is the more precise choice.
Example: A 15-inch laptop bag is 15 × 2.54 = 38.1 cm wide. A 50 cm shelf is 50 ÷ 2.54 = 19.7 inches.
For rough mental math, “multiply by 2.5” gets you close. It undercounts by about 1.6%. That gap matters for large numbers or tight fits, so use 2.54 when the size really matters.
Quick conversion chart
Inches to centimeters
| Inches | Centimeters |
|---|---|
| 1 in | 2.5 cm |
| 2 in | 5.1 cm |
| 3 in | 7.6 cm |
| 4 in | 10.2 cm |
| 5 in | 12.7 cm |
| 6 in | 15.2 cm |
| 7 in | 17.8 cm |
| 8 in | 20.3 cm |
| 9 in | 22.9 cm |
| 10 in | 25.4 cm |
| 11 in | 27.9 cm |
| 12 in (1 ft) | 30.5 cm |
| 24 in (2 ft) | 61.0 cm |
| 36 in (3 ft / 1 yd) | 91.4 cm |
Centimeters to inches
| Centimeters | Inches |
|---|---|
| 10 cm | 3.9 in |
| 30 cm | 11.8 in |
| 100 cm (1 m) | 39.4 in |
One useful detail: a 30 cm school ruler is a little shorter than a foot. One foot is 30.48 cm, and 30 cm is about 11.8 inches.
Converting height in feet and inches
Height is often written as feet and inches, such as 5′7″ (“5 feet 7 inches”). A foot is 12 inches, so converting takes two steps:
- Convert everything to inches: (feet × 12) + inches.
- Multiply the total by 2.54.
Example: 5 ft 7 in → (5 × 12) + 7 = 67 inches → 67 × 2.54 = 170.2 cm.
| Height | Total inches | Centimeters |
|---|---|---|
| 5 ft 0 in | 60 in | 152.4 cm |
| 5 ft 4 in | 64 in | 162.6 cm |
| 5 ft 7 in | 67 in | 170.2 cm |
| 5 ft 10 in | 70 in | 177.8 cm |
| 6 ft 0 in | 72 in | 182.9 cm |
A common mistake is to treat “5.7 feet” as 5 ft 7 in. They are different. 5.7 feet equals 5 ft 8.4 in, because 0.7 of a foot is 8.4 inches, not 7.
TV and monitor sizes: what the inches really mean
A “55-inch TV” is not 55 inches wide. Screen sizes are measured diagonally, from one corner of the visible picture to the opposite corner. To find out whether a TV will fit on a wall or in a cabinet, you need the width and height.
Most TVs and many monitors use a 16:9 aspect ratio. That means the screen is 16 units wide for every 9 units tall. The diagonal of a 16 × 9 rectangle is √(16² + 9²) = √337 ≈ 18.3576 units. That gives two handy multipliers:
- Width = diagonal × 0.8716 (16 ÷ 18.3576)
- Height = diagonal × 0.4903 (9 ÷ 18.3576)
Multiply the result by 2.54 to get centimeters. Here are common sizes:
| Advertised size | Diagonal (cm) | Screen width | Screen height |
|---|---|---|---|
| 32 in | 81.3 cm | 27.9 in / 70.8 cm | 15.7 in / 39.8 cm |
| 43 in | 109.2 cm | 37.5 in / 95.2 cm | 21.1 in / 53.5 cm |
| 50 in | 127.0 cm | 43.6 in / 110.7 cm | 24.5 in / 62.3 cm |
| 55 in | 139.7 cm | 47.9 in / 121.8 cm | 27.0 in / 68.5 cm |
| 65 in | 165.1 cm | 56.7 in / 143.9 cm | 31.9 in / 80.9 cm |
| 75 in | 190.5 cm | 65.4 in / 166.0 cm | 36.8 in / 93.4 cm |
Bezels and stands make the TV bigger
These numbers describe the visible screen only. The real product is larger because of the bezel, which is the frame around the screen. A stand also adds height and needs depth. Thin-bezel models may add only a small amount, while others add more. Before you buy furniture or a wall mount, check the “dimensions without stand” and “dimensions with stand” figures in the manufacturer’s specifications. Use the table above for comparing screen sizes, not for exact fitting.
Ultrawide monitors (21:9) and older 4:3 screens have different proportions, so the 16:9 multipliers do not apply to them.
How to convert inches to cm with Deftivo
If you’d rather not do the math by hand, the Deftivo unit converter does it in your browser. Nothing is sent to a server.
- Open the unit converter.
- Choose the Length category.
- Type your number and pick its unit from the list, for example Inch (in).
- Read the table below: it shows the value in every length unit at once, including centimeters, feet and meters. For centimeters to inches, pick Centimetre (cm) as the unit instead.
For height in feet and inches, first add up the total inches as shown above (feet × 12 + inches). Then convert that single number.
Tips and pitfalls
- Round at the end, not in the middle. If you round 0.8716 or the screen width before converting to cm, small errors add up. Keep full numbers until the last step.
- Check the symbol. ″ (or “) means inches and ′ (or ’) means feet. Mixing them up is a common source of big mistakes.
- Know your ratio. The TV width and height multipliers only work for 16:9 screens.
- Leave clearance. When you fit something into a space, allow a little extra room for cables, ventilation and the frame.
- Watch decimal feet. Some forms use decimal feet (5.5 ft = 5 ft 6 in). Convert carefully.
FAQ
Is 1 inch exactly 2.54 cm or just approximately?
It is exact. The inch is officially defined as 2.54 centimeters, so multiplying by 2.54 adds no rounding error. Any rounding only comes from how many decimals you keep in the answer.
How do I convert centimeters to inches quickly?
Divide the centimeters by 2.54. For a rough estimate in your head, divide by 2.5, or multiply by 4 and then divide by 10. For example, 30 cm is about 12 inches by the rough method and exactly 11.8 inches with 2.54.
How wide is a 65-inch TV in centimeters?
A 16:9, 65-inch screen is about 143.9 cm wide and 80.9 cm tall. Those numbers cover the visible picture only. The full TV is somewhat larger because of the bezel, and taller with the stand, so check the manufacturer’s listed dimensions before you measure your space.
How do I convert 5 ft 7 in to centimeters?
Convert to inches first: 5 × 12 + 7 = 67 inches. Then multiply by 2.54 to get 170.2 cm. You can also enter 67 inches in the Deftivo unit converter under Length.