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Resize Image in cm, mm or Inches - Photo and Signature Size Tool

Type a width and height in centimetres, millimetres or inches, pick a DPI and download a picture that prints at exactly that size.

What is Resize in cm / mm / inch?

Physical size depends on both the pixel dimensions and the DPI (dots per inch). A 3.5 x 4.5 cm passport photo at 300 DPI is about 413 x 531 pixels. This tool does the maths for you: enter the size in cm, mm or inches, choose the DPI, and it creates the image with the right number of pixels. It is ideal for passport photos, ID cards, exam photos and signatures.

How to use Resize in cm / mm / inch

1Upload your photo or signature.

2Enter the width and height, and choose cm, mm or inch.

3Set the DPI - 300 is standard for print and most forms.

4Press Start and download the resized image.

Why use Resize in cm / mm / inch?

Converts real-world sizes to pixels automatically.
Common sizes like 3.5 x 4.5 cm and 2 x 2 inch are quick to enter.
Free, private and instant.
Works for photos, signatures, stamps and documents.

Who can use Resize in cm / mm / inch?

Candidates applying for exams, jobs and government schemes.
People preparing passport, visa or ID card photos.
Print shops and photographers.
Students submitting scanned signatures.

When should you use it?

When a form says 'photo size 3.5 cm x 4.5 cm'.
When you want a picture to print at an exact size.
When a signature must be 6 cm x 2 cm.

Where can you use it?

Use it before uploading photos to application portals.
Works in Chrome, Edge, Firefox and Safari on Windows, Mac, Linux, Android and iPhone - no app or software to install.

Tips for best results

Use 300 DPI unless the portal gives another value.
Start from a sharp, high-resolution original for the best result.
If the file becomes too large, compress it with Compress Image to KB.

Resize in cm / mm / inch - frequently asked questions

How do I resize an image to 3.5 cm x 4.5 cm?

Choose cm, enter 3.5 for width and 4.5 for height, keep 300 DPI and press Start. The result is about 413 x 531 pixels.

What DPI should I use?

300 DPI is the usual choice for print and for most government forms.

What is the difference between pixels and cm?

Pixels are the dots in the image. Centimetres describe the printed size, which depends on the DPI.

Can I resize a signature to a given size?

Yes. Upload the signature image, enter its width and height and press Start.

Does it work on mobile?

Yes. It works in any modern browser on phones and tablets.

Is it free and private?

Yes. AllrounderBox is free, needs no sign-up and never uploads your files – processing happens on your own device.