Resize images to exact centimetre dimensions with DPI control for print. Free, and it runs entirely in your browser — nothing is uploaded to a server. No account, no watermark, no limits.
Resize an image by centimeters to prepare it for print at an exact physical size, all inside your browser. This free cm image resizer converts your centimeter dimensions and DPI into the right pixel count, so a photo printed at 10 x 15 cm or an A4 page at 21 x 29.7 cm comes out crisp and correctly scaled. Processing is 100% client-side with WebAssembly and Canvas, meaning your images are never uploaded, and the tool is free with no account, watermark, or limits.
Screens are measured in pixels, but printers and paper are measured in physical units like centimeters. When your goal is a printed photo, poster, flyer, or document that must be a specific physical size, thinking in centimeters is far more intuitive than guessing pixel counts. You tell the tool the real-world size you want, and it handles the pixel math.
The bridge between centimeters and pixels is DPI (dots per inch), also expressed as PPI (pixels per inch). DPI defines how many pixels are packed into each inch of print. Higher DPI means more pixels per centimeter, sharper prints, and larger pixel dimensions for the same physical size.
One inch equals 2.54 centimeters, so the core formula is: pixels = (centimeters / 2.54) x DPI. To go the other way: centimeters = (pixels / DPI) x 2.54. Setting the correct DPI is what makes the difference between a sharp print and a pixelated one.
For quality prints, 300 DPI is the professional standard, 150 DPI is acceptable for larger posters viewed from a distance, and 72 DPI is screen-only and too low for print. Enter your size in centimeters, choose your DPI, and the tool calculates the exact pixel dimensions needed.
Many standard photo and paper sizes are defined in centimeters or convert cleanly to them. Use these as ready targets, then choose 300 DPI for photo-quality output.
When you lock the aspect ratio, entering one centimeter dimension auto-fills the other so your photo keeps its true proportions. This matters even more in print, where a stretched face or squashed logo is obvious on paper.
If your desired print size has a different shape than your original photo (for example a square print from a wide photo), resize with the ratio locked to fit and crop the rest, rather than forcing both dimensions and distorting the image.
Print is unforgiving of low resolution, so start from the highest-quality original you have. If your source image does not contain enough pixels for your chosen size at 300 DPI, the tool must upscale, which softens detail. For example, a large poster at 300 DPI needs a lot of pixels, and a small phone screenshot simply may not have them.
A quick check: multiply your target pixel dimensions and make sure your original is close to or larger than that. If it falls short, either use a bigger source image, accept a slightly lower DPI like 150 for big prints viewed from a distance, or reduce the physical size.
All the centimeter-to-pixel conversion and resizing happens locally in your browser, so your images are never uploaded and nothing is stored on a server. The tool works offline after loading, and there is no account, watermark, or limit on how many images you prepare for print.
10 cm at 300 DPI is 1181 pixels. The formula is pixels = (cm / 2.54) x DPI, so (10 / 2.54) x 300 = 1181 px. At 150 DPI, 10 cm would be 591 pixels.
Use pixels = (centimeters / 2.54) x DPI. First divide the centimeters by 2.54 to get inches, then multiply by your DPI. The cm resizer does this automatically once you enter your size and DPI.
Use 300 DPI for photos and detailed prints, which is the professional standard. 150 DPI is acceptable for large posters viewed from a distance, while 72 DPI is only for screens and will look pixelated in print.
Open the CM resizer, enter 10 cm width and 15 cm height, set DPI to 300, and download. This produces about 1181 x 1772 pixels, the standard size for a 4 x 6 inch photo print.
A4 is 21 x 29.7 cm. At 300 DPI that is about 2480 x 3508 pixels, and at 150 DPI about 1240 x 1754 pixels. Enter 21 x 29.7 cm and choose your DPI to get a print-ready A4 image.
Use centimeters = (pixels / DPI) x 2.54. For example, a 1181-pixel-wide image at 300 DPI is (1181 / 300) x 2.54 = about 10 cm wide. The physical size depends entirely on the DPI you print at.
Your original likely does not have enough pixels for that physical size at your chosen DPI, so the tool has to upscale and invent detail. Use a higher-resolution source, lower the DPI for large posters, or reduce the print size.
No. All conversion and resizing happens in your browser with WebAssembly and Canvas, so images never leave your device. There is no upload, no server, and the tool works offline once loaded.
Yes. It is completely free with no account, no watermark, and no limit on the number of images. You can prepare as many print-ready images as you need.
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