Photo Size Converter
Convert PX, CM, MM and inches using DPI.
Photo Size Converter — PX, CM, MM & Inches
Photo Size Converter converts physical print measurements (CM) and DPI into exact pixel dimensions using the formula pixels = (millimetres ÷ 25.4) × DPI.
Supported formats: PX · CM · MM · Inches · Processing: 100% browser-local HTML5 Canvas & Blob APIs
How to use Photo Size Converter
- Select your source photo from your device.
- Enter the desired physical Width and Height and verify the measurement unit (CM, MM, Inches, or PX).
- Set the target DPI (300 DPI is standard for print and official photo submissions; 96–150 DPI is common for screen use).
- Check the "Calculated output" pixel readout, click Process, and download the finished file with embedded DPI metadata.
Practical use cases
- Converting 3.5 × 4.5 cm or 35 × 45 mm requirements into exact 413 × 531 px images at 300 DPI.
- Preparing print-ready images in centimetres, millimetres, or inches for lab printing and ID cards.
- Switching seamlessly between physical units and pixel dimensions without manual math.
Common size & DPI reference specifications
| Preset / Format | Physical Size | Pixels at 300 DPI | Common Application |
|---|---|---|---|
| 35 × 45 mm | 3.5 × 4.5 cm | 413 × 531 px | Standard ICAO / UK / EU / Australia passport & visa photos |
| 2 × 2 inch | 50.8 × 50.8 mm | 600 × 600 px | US passport, OCI card, and square visa applications |
| 25 × 35 mm | 2.5 × 3.5 cm | 295 × 413 px | PAN card, academic admit cards, and compact ID badges |
| A4 Photo Sheet | 210 × 297 mm | 2480 × 3508 px | Multi-photo printable sheet with cut guide borders |
Common problems & solutions
Solution: If your original photo is widescreen and you resize directly to 35 × 45 mm without cropping, the face may look narrow. Use Passport Photo Maker to crop and size simultaneously.
Solution: Check that you entered 3.5 cm (not 35 cm) or 35 mm, and verify DPI is set to 300 rather than 1200.
Are my images uploaded to AJN Buzz?
No for this tool. Processing runs in your browser and no sign-in is required.
How are physical units converted to pixels?
Inches are multiplied by DPI (pixels = inches × DPI). Centimetres are divided by 2.54 then multiplied by DPI, and millimetres are divided by 25.4 then multiplied by DPI.
Does the downloaded file include the selected DPI in its header?
Yes. JPG outputs include the JFIF density header and PNG outputs include the pHYs chunk matching your selected DPI.
Overview · Photo Size Converter
Switch between physical units and pixels, see the calculated output dimensions, and create the resized photo.
Tool preview