Quick answer: 1 inch is exactly 2.54 cm. That one number builds the whole inches to cm chart below: a 55 inch TV has a 139.7 cm diagonal, a 32 inch jeans waist is 81 cm, a 28 inch bike wheel is 71 cm. The 2.54 is not a rounding: it is the international definition of the inch (NIST).
For any other length, the cm to inches converter works it out live, fractions included.
Inches follow you through every purchase: screens, jeans, bikes, phones. And the most expensive mistake is not the conversion itself, it is what the number measures.
The inches to cm chart you actually need
| Inches | Centimetres | Where you meet it |
|---|---|---|
| 6.7” | 17 cm | Phone screen diagonal |
| 24” | 61 cm | Desk monitor |
| 27” | 68.6 cm | Desk monitor |
| 28” | 71 cm | Bike wheel (city bikes) |
| 30” | 76 cm | Jeans waist W30 |
| 32” | 81 cm | Jeans W32, small TV |
| 43” | 109 cm | Living-room TV |
| 55” | 140 cm | The most sold TV size |
| 65” | 165 cm | Large TV |
| 75” | 190.5 cm | Home cinema |
TV sizes in cm: the TV-stand mistake
TV inches measure the diagonal of the panel, corner to corner, so the screen size on the box is not the width. A 55 inch TV is 140 cm diagonally, but its width is about 122 cm (16:9 panel, before the bezel). If your TV stand is 120 cm wide, the diagonal number says it fits and reality says it does not. That is the trap of every TV size chart: convert the diagonal, then check the width spec in cm.
Same logic for jeans: W32 means a 32 inch jeans waist, about 81 cm, and brands round differently. For bikes, 26, 28 and 29 inches describe the bike wheel, not the frame.
The maths, once and for all
Multiply inches by 2.54 to get centimetres. Divide centimetres by 2.54 to get inches. That is the whole trick, and every line of the inches to cm chart above comes from it: 55 × 2.54 = 139.7 cm.
A 55 inch TV: how wide is it, roughly?
TV sizes are diagonals. A 55 inch (140 cm) 16:9 panel is about 122 cm wide, plus the bezel.
The app answers this kind of question in one tap.
In the shop aisle, one tap
Standing in front of the TV wall, type 55 into Conversion Calculator and the inch to cm conversion is done: centimetres appear instantly, along with every other length unit. It handles compound sizes like 2ft6 too, the kind furniture listings love. And if that purchase flies home with you, check the 23 kg luggage trap before packing it.
Get the app free and measure before you pay.