Rekto DigitalFree toolsResize image in cm
Resize an image in cm
Updated October 28, 2026 · Free, no sign-up, no upload
Set the width and height in centimetres and the DPI: the tool works out the pixels (cm ÷ 2.54 × DPI), lets you frame the photo, and gives you a JPG that prints at exactly that size.
Centimetres to pixels
pixels = cm ÷ 2.54 × DPI
An inch is 2.54 cm, and DPI is how many pixels fit in one inch when printed. So at 300 DPI, a 3.5 cm wide passport photo is 3.5 ÷ 2.54 × 300 = 413 pixels wide.
Common sizes in pixels
| Size (cm) | 300 DPI | 150 DPI | 96 DPI |
|---|---|---|---|
| 2 × 2.5 | 236 × 295 | 118 × 148 | 76 × 94 |
| 3.5 × 4.5 (passport) | 413 × 531 | 207 × 266 | 132 × 170 |
| 5 × 5 | 591 × 591 | 295 × 295 | 189 × 189 |
| 10 × 15 (4 × 6 in) | 1181 × 1772 | 591 × 886 | 378 × 567 |
| 13 × 18 | 1535 × 2126 | 768 × 1063 | 491 × 680 |
| 15 × 20 | 1772 × 2362 | 886 × 1181 | 567 × 756 |
| 21 × 29.7 (A4) | 2480 × 3508 | 1240 × 1754 | 794 × 1123 |
Questions
How do I convert cm to pixels?
Pixels = cm ÷ 2.54 × DPI. At 300 DPI, 1 cm is about 118 pixels, so a 10 cm wide photo is 1181 pixels. At 96 DPI, the usual screen setting, 1 cm is about 38 pixels.
Which DPI should I choose?
300 DPI for printing: photo labs and printers use it for sharp prints. 150 to 200 DPI is fine for large posters seen from a distance. 72 or 96 DPI only matter for screens, where the pixel size is what counts.
What if my photo has a different shape?
Fill in both width and height and the tool shows a frame of that shape: drag and zoom to choose what to keep, and the rest is cropped. Leave the height empty to keep the photo's own shape.
Will it print at exactly this size?
Yes, if you print at 100% (actual size) rather than "fit to page": the tool writes the DPI into the JPG, so printers and photo apps know its size in centimetres.
Is my photo uploaded?
No. Everything happens in your browser on your own device; the photo is never sent to our server or anyone else's.
Making a passport photo?The passport size photo maker has the sizes for India, the US, the UK and Europe, Canada and more, and makes a 4 × 6 print sheet.