Centimetres to pixels: photo and signature sizes
Forms give sizes in centimetres, but images are measured in pixels. The two are linked by DPI (dots per inch): pixels = centimetres ÷ 2.54 × DPI. If your form does not mention DPI, 200 is a safe choice for photos and signatures.
Converter
3.5 × 4.5 cm at 200 DPI = 276 × 354 pixels
Ready to resize? Make an image to these exact requirements — enter the same width, height, unit and DPI there.
Common form sizes in pixels
| Size | 100 DPI | 200 DPI | 300 DPI | Tool |
|---|---|---|---|---|
| 3.5 × 4.5 cm (passport-style photo) | 138 × 177 | 276 × 354 | 413 × 531 | Open |
| 2.5 × 3.5 cm (PAN photo) | 98 × 138 | 197 × 276 | 295 × 413 | Open |
| 4.5 × 2 cm (PAN signature) | 177 × 79 | 354 × 157 | 531 × 236 | Open |
| 6 × 2 cm (signature) | 236 × 79 | 472 × 157 | 709 × 236 | Open |
| 3.5 × 1.5 cm (signature) | 138 × 59 | 276 × 118 | 413 × 177 | Open |
| 5.1 × 5.1 cm (2 × 2 inch photo) | 200 × 200 | 400 × 400 | 600 × 600 | Open |
| A4 page (21 × 29.7 cm) | 827 × 1169 | 1654 × 2339 | 2480 × 3508 | Open |
Pixels are not kilobytes
Pixels describe the picture’s width and height. KB describes the file size, which also depends on JPG quality and how much detail the picture has. A 200 × 230 pixel photo is usually 10–30 KB; a 600 × 600 photo is usually 40–120 KB. That is why forms often give both a pixel size and a KB range. Set the pixels first, then let the tool search for the best quality inside the KB limit: photo under 20 KB, under 50 KB, signature under 20 KB.
Does DPI change the file?
Not on its own. A 413 × 531 pixel image is the same picture whether it is labelled 72 or 300 DPI. DPI only matters for converting a physical size into pixels and for printing. Some portals also read the DPI value stored in the file; FileFatafat writes the DPI you choose into the exported JPG.
All exam and form sizes in one place: photo and signature size chart.
Questions
What is 3.5 × 4.5 cm in pixels?
At 200 DPI it is 276 × 354 pixels; at 300 DPI it is 413 × 531 pixels; at 100 DPI it is 138 × 177 pixels.
What is 6 cm × 2 cm in pixels?
At 200 DPI it is 472 × 157 pixels; at 300 DPI it is 709 × 236 pixels.
How many pixels is 1 cm?
At 200 DPI one centimetre is about 79 pixels; at 300 DPI it is about 118 pixels; at 96 DPI (a typical screen) about 38 pixels.
What is a 10 KB photo in pixels?
KB is file size, not picture size, so there is no single answer. Small passport-style photos of about 160 × 200 to 200 × 230 pixels usually fit under 10 KB at reasonable quality.