By Ahsan Khowaja · Updated 27 October 2026
How to convert pixel dimensions to cm
- Leave single length selected to convert one number (how long is 350 px?), or switch to image size to convert a width and height at once.
- Type the pixels.
- Choose a resolution. The default is 96 PPI, the value CSS and Windows use for screens, so it answers the everyday "how big is 100 px?" question. Switch to 300 DPI to see how large the same pixels come out on photo paper, or use Custom.
- Read the centimetres, the millimetres and the inches. The table below the result repeats the conversion at each other resolution so you can compare screen and print at a glance.
Whether you spell it pixels to centimeters or centimetres, the resolution matters because a pixel is a count, not a length. A stretch of 1080 pixels is 28.575 cm across a 96 PPI screen and 9.144 cm on a 300 DPI print. Same pixels, different density, different size.
Formula: cm = pixels ÷ PPI × 2.54
Two steps. First divide the pixels by the pixels per inch to get inches. Then multiply by 2.54, because an inch is defined as exactly 2.54 centimetres. Written as one line:
cm = px ÷ PPI × 2.54, and mm = px ÷ PPI × 25.4.
- 100 px to cm at 96 PPI: 100 ÷ 96 = 1.0417 in; × 2.54 = 2.646 cm (26.458 mm).
- 200 pixels in cm: 200 ÷ 96 × 2.54 = 5.292 cm. At 300 DPI it is 1.693 cm.
- 350 pixels in cm: 350 ÷ 96 × 2.54 = 9.26 cm; at 300 DPI, 2.963 cm.
- 1080 pixels in cm: 1080 ÷ 96 × 2.54 = 28.575 cm, or 9.144 cm at 300 DPI.
At 96 PPI each pixel is 2.54 ÷ 96 = 0.026458 cm, so a quick mental version is "pixels × 0.0265" for screen centimetres. For print at 300 DPI the factor is 2.54 ÷ 300 = 0.008467 cm per pixel.
How many px are in 1 cm, and what is 1 pixel in mm?
On the web, the relationship is fixed by the CSS standard. CSS Values and Units Level 4 defines 1in as 96px and 1cm as 96px ÷ 2.54, so 1 cm is 37.795 px and 1 pixel is 0.02646 cm, or 0.2646 mm. Those are CSS pixels; a high-density phone draws each one with several physical pixels, which is how a 6 inch phone can show more pixels than a 24 inch monitor. A Windows PC at 100 % scaling also uses 96 PPI.
In print, 1 pixel is as wide as the printer makes it: at 300 DPI, 1 pixel is 0.0847 mm, and 1 cm holds 118 pixels. The cm to pixels converter does the division for any resolution, and the PPI calculator works out a real screen's density from its diagonal and resolution.
Pixels to cm lookup table
The lengths searched for most, at screen density (96 PPI) and at print density (300 DPI). Values are rounded to three decimals, or four for lengths under 1 cm.
| Pixels | At 96 PPI (CSS) | In mm at 96 PPI | At 300 DPI (print) |
|---|---|---|---|
| 1 px | 0.0265 cm | 0.2646 mm | 0.0085 cm |
| 5 px | 0.1323 cm | 1.323 mm | 0.0423 cm |
| 10 px | 0.2646 cm | 2.646 mm | 0.0847 cm |
| 20 px | 0.529 cm | 5.292 mm | 0.169 cm |
| 50 px | 1.323 cm | 13.229 mm | 0.423 cm |
| 100 px | 2.646 cm | 26.458 mm | 0.847 cm |
| 200 px | 5.292 cm | 52.917 mm | 1.693 cm |
| 300 px | 7.938 cm | 79.375 mm | 2.54 cm |
| 350 px | 9.26 cm | 92.604 mm | 2.963 cm |
| 500 px | 13.229 cm | 132.292 mm | 4.233 cm |
| 1000 px | 26.458 cm | 264.583 mm | 8.467 cm |
| 1024 px | 27.093 cm | 270.933 mm | 8.67 cm |
| 1080 px | 28.575 cm | 285.75 mm | 9.144 cm |
| 1920 px | 50.8 cm | 508 mm | 16.256 cm |
Two of these are worth remembering. 300 px at 300 DPI is exactly 2.54 cm (one inch), and 1920 px at 96 PPI is exactly 50.8 cm (twenty inches). Everything else follows from the 2.54 definition.
Pixels to cm for printing: image sizes in centimetres
Width × height for common image sizes, at 300 DPI (the size a lab prints them without losing sharpness) and at 96 PPI (the size a browser or Windows assigns them):
| Image (px) | At 300 DPI | At 96 PPI | Nearest metric print |
|---|---|---|---|
| 1080 × 1080 | 9.144 × 9.144 cm | 28.575 × 28.575 cm | 9 × 9 cm square |
| 1080 × 1350 | 9.144 × 11.43 cm | 28.575 × 35.719 cm | 9 × 13 cm with a small crop |
| 1200 × 1800 | 10.16 × 15.24 cm | 31.75 × 47.625 cm | 10 × 15 cm |
| 1920 × 1080 | 16.256 × 9.144 cm | 50.8 × 28.575 cm | 15 × 10 cm (landscape) |
| 2480 × 3508 | 20.997 × 29.701 cm | 65.617 × 92.816 cm | A4 (21 × 29.7 cm) |
| 3000 × 2000 | 25.4 × 16.933 cm | 79.375 × 52.917 cm | 25 × 17 cm, or 20 × 30 at 254 DPI |
| 4032 × 3024 | 34.138 × 25.603 cm | 106.68 × 80.01 cm | 30 × 40 cm at 256 DPI |
| 6000 × 4000 | 50.8 × 33.867 cm | 158.75 × 105.833 cm | 50 × 75 cm at 203 DPI |
The last column shows the trade-off: a 3000 × 2000 px photo fills a 20 × 30 cm print at 254 DPI rather than 300, which is still sharp in the hand. The DPI calculator gives the effective DPI for any print, and the print size calculator lists what a given photo supports. A4 at 300 DPI is 2480 × 3508 px, which is why that odd-looking size appears so often in document scans.
Pixels and centimetres in CSS
CSS lets you write lengths in cm, mm and in as well as px, and converts them with the fixed 96 PPI ratio: width: 10cm is 377.95 px, 1mm is 3.78 px. Browsers do not measure the real screen, so 10cm only comes out as 10 physical centimetres on a display that happens to be 96 PPI. For screens, stick to px, rem and %; for print stylesheets, cm and mm are useful because the printer's inch is real. The px to rem converter covers the other common CSS conversion, and MDN's length reference lists every unit.
If you are measuring something in a photo rather than the photo itself, pixels only become centimetres once you know the scale: photograph a ruler in the same plane, count how many pixels one centimetre covers, and divide. A 4032 px wide photo in which a 30 cm ruler spans 1500 px has a scale of 50 px per cm, so an object 400 px long is 8 cm.
