What this does
Converts inches to centimeters the moment you type. The formula is cm = inches × 2.54, and the factor is exact — an inch has been defined as 2.54 cm since 1959. The page opens with 1 inch entered, showing 2.54 cm. Both fields are live, so you can type centimeters on the right and read inches on the left; the ⇄ button swaps the units while keeping the left-hand number. Results are rounded to six decimals. It runs in your browser, so it works offline.
What is the exact formula for inches to cm?
Multiply by 2.54. Because 2.54 has two decimal places, any inch value with up to four decimals converts with nothing to round: 15.6 in × 2.54 = 39.624 cm, done. The six-decimal cap only bites when you type a repeating decimal. Worked example: a third of an inch entered as 0.333333 gives 0.333333 × 2.54 = 0.84666582, which the tool shows as 0.846666. A mental shortcut is "×2.5, then add a little": 10 in → 25 → 25.4; 40 in → 100 → 101.6.
Inches to centimeters at a glance
| Inches | Centimeters | Where it appears |
|---|---|---|
| 0.5 | 1.27 | a ½″ pipe or bolt |
| 4 | 10.16 | a 4″ phone-camera print |
| 6.5 | 16.51 | a "6.5-inch" phone screen diagonal |
| 8.5 × 11 | 21.59 × 27.94 | US Letter paper (A4 is 21 × 29.7 cm) |
| 15.6 | 39.624 | the commonest laptop screen |
| 27 | 68.58 | a desktop monitor |
| 29 | 73.66 | a mountain-bike wheel |
| 65 | 165.1 | a living-room TV |
How do I convert fractions of an inch, like 3 5/8?
Turn the fraction into a decimal and add it to the whole inches: 5 ÷ 8 = 0.625, so 3 5/8″ is 3.625 in, which converts to 9.2075 cm. Imperial hardware and lumber are quoted in halves, quarters, eighths and sixteenths — one sixteenth is 0.0625 in, or 1.5875 mm — so a 9/16″ wrench is 14.2875 mm, which is why it fits a 14 mm bolt loosely and a 15 mm one not at all.
How big is a 15.6-inch laptop or a 65-inch TV in cm?
Screen sizes are diagonals, so multiply by 2.54: 13.3″ is 33.782 cm, 15.6″ is 39.624 cm, 27″ is 68.58 cm, 55″ is 139.7 cm, 65″ is 165.1 cm. The diagonal alone doesn't tell you whether it fits on the wall — a 65″ 16:9 TV is about 144 cm wide by 81 cm tall, and you'll need the aspect ratio to work out the sides for other shapes. Waist sizes are the other daily case: a 32″ waist is 81.28 cm, a 34″ is 86.36 cm.
Where does inches to cm come up in real life?
Anywhere a US-designed product meets a metric tape measure: screens, tyre and wheel sizes, pipe threads, vinyl records, photo prints, US clothing charts, and mattress or furniture listings on American sites. It also goes the other way — an American filling in a European form that asks for shoulder width or foot length in centimeters. Note that US clothing "inches" are nominal: a 32″ waist jean can measure 84 cm laid flat.
Can I convert centimeters to inches here?
Yes — type in the right-hand box and the inches side recomputes, or hit ⇄. The dropdowns also carry every other length unit (millimeters, meters, feet, yards, miles and more), since only the category tabs are hidden. For the reverse direction written for someone reading metric heights and luggage sizes, see cm to inches; the full unit converter has weight, temperature and everything else.