Resize an image in centimetres

FreeNo uploadNo signupWorks offline

Photo labs, application forms and print shops ask for a size in centimetres, but an image file has no physical size of its own - only pixels. Enter the size you need and the resolution, and the right pixel dimensions are worked out for you, on your device.

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How to use Resize Image in cm

Resize Image in cm – Set an image to a print size in centimetres, at the DPI you choose. Free, no upload.

Choose or drop your image.
Enter the width and height in centimetres.
Set the resolution - 300 DPI for photo prints, 150 for documents.
Click Resize and download.

Supported formats

Input: JPG, PNG, WebP, AVIF, HEIC
Output: Same as input, JPG, PNG

Why centimetres alone are not enough

An image file is a grid of pixels; it has a physical size only once you decide how many pixels go into each centimetre. That number is the DPI. At 300 DPI a one-centimetre square is 300 pixels across; at 72 DPI the same square is 72 pixels and will look blocky in print. This is why a photo that looks sharp on screen can print badly: the screen was showing it at a size the pixel count could support, and the print is not.

Which DPI to choose

300 DPI is the standard for anything printed and looked at closely - photo prints, passport photos, anything submitted to an office. 150 DPI is fine for a document that will be read at arm’s length, and halves the pixel count. Below 150 the result starts to look soft in print even though it may look fine on a screen. Going above 300 rarely helps: most printers cannot resolve the extra detail, and the file gets large for nothing.

Common sizes in centimetres

What each size is normally used for, and the pixel dimensions it needs at 300 DPI.

Print sizes in centimetres at 300 DPI
Size (cm)	Normally used for	Pixels at 300 DPI
3.5 × 4.5 cm	Passport and visa photo across most of Europe and India	413 × 531 px
5 × 7 cm	Small print, common for application forms	591 × 827 px
10 × 15 cm	Standard photo print (6 × 4 inches)	1181 × 1772 px
21 × 29.7 cm	A4 - a full page	2480 × 3508 px
6 × 2 cm	Signature strip on Indian exam forms	709 × 236 px

If the image does not have enough pixels

Resizing changes the pixel count, so asking for a large print from a small image means enlarging, and enlarging cannot add detail that was never captured. If the result looks soft, the honest fix is a higher-resolution original rather than a higher DPI setting - raising DPI on a small image just spreads the same pixels more thinly.

Limitations

Enlarging to a bigger print size cannot add detail that was never captured.
The DPI value is used to work out the pixel size; some print shops also want it written into the file’s metadata, which this tool does not set.

Privacy

Files you choose are read into your browser’s memory and processed on your device; they are not uploaded to a server. Temporary download links are released after use, and the offline cache never stores your documents. More about privacy and limits.

Frequently asked questions

How many pixels is one centimetre?

It depends on the DPI. At 300 DPI, one centimetre is 300 pixels; at 150 DPI it is 150. There is no fixed answer, which is why forms that ask for centimetres should also state a DPI.

Can I resize in inches instead?

Yes - the general Resize Image tool offers pixels, percentage, centimetres and inches in one place.

What DPI do passport photos need?

Most authorities ask for 300 DPI. Check the notice for your country, because a few state a pixel size instead, which removes the ambiguity entirely.

Will resizing blur the image?

Making an image smaller uses Lanczos-3 resampling, which keeps edges crisp. Enlarging cannot invent detail that was never captured, so a large upscale will always look soft.

Is my image uploaded?

No. It is resized in your browser, on your device. Nothing is sent to a server, which matters when the image is an ID photo or a signature.

Is it free?

Yes - free, no signup, no watermark and no limit on how many images you resize.