Resize Image in CM and Inches
Type the print size you need in centimeters, millimeters or inches, choose the DPI, and the tool works out the exact pixel dimensions, resizes your photo and saves the DPI in the file so it prints at exactly that size. Download as JPG, PNG or a PDF page of the same size.
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How to use the Resize Image in CM and Inches
- Add your photo by dropping it in, choosing a file or pasting it. A sample image is used until you do.
- Choose the unit (cm, mm or inches) and type the width or height, or click a ready-made size such as 3.5 × 4.5 cm.
- Pick the DPI: 300 for photo prints, 150-200 for posters seen from a distance, 72-96 for screen use.
- Decide the fit if you unlock the ratio: crop to fill, fit inside a white border, or stretch.
- Check the pixel size and sharpness note, choose JPG, PNG or PDF, then click Download.
From centimeters and inches to pixels
A digital image has no physical size, only a number of pixels. The print size appears when you decide how many pixels go into each inch: the DPI (dots per inch, often called PPI for images). The conversion is simple:
- pixels = inches × DPI
- pixels = centimeters ÷ 2.54 × DPI (one inch is exactly 2.54 cm)
- pixels = millimeters ÷ 25.4 × DPI
So a 10 × 15 cm print at 300 DPI needs 10 ÷ 2.54 × 300 = 1181 by 15 ÷ 2.54 × 300 = 1772 pixels. The tool resamples your photo to exactly that pixel count and stores 300 DPI in the file, so photo-printing software and word processors place it at 10 × 15 cm automatically.
Common print sizes in pixels
| Print size | In cm / inches | At 150 DPI | At 300 DPI |
|---|---|---|---|
| ID / passport style photo | 3.5 × 4.5 cm | 207 × 266 px | 413 × 531 px |
| Square ID photo | 2 × 2 in (5.08 × 5.08 cm) | 300 × 300 px | 600 × 600 px |
| Standard photo print | 4 × 6 in (10.16 × 15.24 cm) | 600 × 900 px | 1200 × 1800 px |
| Metric photo print | 10 × 15 cm | 591 × 886 px | 1181 × 1772 px |
| Enlargement | 5 × 7 in | 750 × 1050 px | 1500 × 2100 px |
| Frame size | 8 × 10 in | 1200 × 1500 px | 2400 × 3000 px |
| A5 paper | 14.8 × 21 cm | 874 × 1240 px | 1748 × 2480 px |
| A4 paper | 21 × 29.7 cm | 1240 × 1754 px | 2480 × 3508 px |
| US Letter | 8.5 × 11 in | 1275 × 1650 px | 2550 × 3300 px |
Tips for sharp prints
- Start from the original photo, not a screenshot or a copy downloaded from a chat app, which are often heavily reduced.
- Watch the sharpness note. It shows the effective resolution of your original at the chosen size. Enlarging a small photo adds pixels but not detail.
- Keep the shape of your photo when you can. If the print size has a different ratio, Crop to fill trims the edges evenly; use Fit + border when nothing may be cut off.
- Print at 100%. In the print dialog choose Actual size or 100% scale instead of Fit to page, otherwise the printer rescales the image.
- Official photos such as passports and visas have their own rules for head size and background; check them with the issuing office.
Frequently asked questions
How do I convert cm to pixels for an image?
Pixels = centimeters ÷ 2.54 × DPI. For example, 10 cm at 300 DPI is 10 ÷ 2.54 × 300 = 1181 pixels. For inches, pixels = inches × DPI, so 4 inches at 300 DPI is 1200 pixels. The tool does this for both sides and rounds to the nearest whole pixel.
What DPI should I use for printing?
300 DPI is the usual standard for photo prints, ID photos and anything viewed up close. 200-240 DPI still looks good for most home prints, 150 DPI is fine for posters viewed from a meter or more, and 72-96 DPI is only meant for screens.
Does changing the DPI change the image?
On its own, DPI is just a number stored in the file that tells printers how big to print it. This tool also resamples the pixels so the image has exactly the pixel count needed for the chosen size at that DPI. If you only want to change the DPI number without touching the pixels, use the Image DPI Changer instead.
What is 3.5 × 4.5 cm in pixels?
At 300 DPI a 3.5 × 4.5 cm photo is 413 × 531 pixels. At 600 DPI it is 827 × 1063 pixels. Always check the exact size and background rules of the office that asked for the photo.
Why does the tool say my image may look blurry?
If your photo has fewer pixels than the size needs, it has to be enlarged and fine detail cannot be recreated. The note shows the effective resolution of your original at the chosen size; above about 200 DPI prints usually look sharp, below about 150 DPI softness becomes visible up close.
What happens when the new size has a different shape?
With the ratio unlocked you choose the behaviour: Crop to fill keeps the center and trims the edges, Fit adds white (or any color) bands so nothing is cut, and Stretch distorts the image to the exact size. With the ratio locked, the other side is calculated automatically.
Will the PDF print at the right size?
Yes. The PDF page is created at exactly the width and height you entered, with the image filling the page. Print it at 100% or Actual size, not Fit to page, so the printer does not scale it.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.