How to resize image
- Choose your image. Its current width and height fill in automatically.
- Pick a unit, then type the new width. The height follows to keep the shape.
- For cm, mm or inches, choose the DPI your form or printer uses (300 for print).
- Tap Resize image, then Download image.
Pixels, centimetres and DPI
Screens measure images in pixels. Paper measures them in centimetres or inches. DPI (dots per inch) connects the two: at 300 DPI, one inch of print uses 300 pixels. So a 3.5 × 4.5 cm photo at 300 DPI is 413 × 531 pixels.
| Print size | At 200 DPI | At 300 DPI |
|---|---|---|
| 3.5 × 4.5 cm (passport) | 276 × 354 px | 413 × 531 px |
| 2 × 2 in (US passport) | 400 × 400 px | 600 × 600 px |
| 4 × 6 in (photo print) | 800 × 1200 px | 1200 × 1800 px |
| A4 page | 1654 × 2339 px | 2480 × 3508 px |
Need the file under a size limit too? Resize first, then use compress image.
Is it safe to upload my photo?
Your image is never uploaded. ResizeKB processes files inside your own browser using the same technology that draws images on web pages, so the photo never leaves your phone or computer. That matters for documents like passport photos, ID scans and signatures. You can even disconnect from the internet after the page loads and the tool keeps working.
Frequently asked questions
Will resizing reduce quality?
Making an image smaller keeps it sharp; the tool uses high-quality step-down scaling. Making it much larger than the original can look soft, because no new detail can be invented.
How do I resize without stretching?
Leave "Keep aspect ratio" ticked. If you need an exact shape, such as square, crop first with the crop tool, then resize.
How do I resize to 3.5 × 4.5 cm?
Set the unit to centimetres, untick aspect ratio, type 3.5 and 4.5, and choose 300 DPI. For face photos, the passport photo maker also lets you frame the crop.
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Last updated 2026-10-27