How it works
Drop in your photo.
Choose cm, type the width, height and DPI from your notice.
Press Resize and download the photo with the DPI recorded.
cm to pixels for exam photos, explained
Why 3.5 × 4.5 cm has no single pixel size, how DPI turns centimetres into pixels, and the numbers for the sizes forms ask for most.
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Centimetres need a DPI
A digital photo has pixels, not centimetres. Centimetres only mean something once you say how many pixels make an inch, the DPI (dots per inch). One inch is 2.54 cm, so pixels = centimetres ÷ 2.54 × DPI. That's why forms that give sizes in cm usually give a DPI too, most often 200.
Common sizes at 200 DPI
3.5 × 4.5 cm (the usual Indian exam and passport photo) is 276 × 354 pixels. 3.5 × 1.5 cm (a common signature box) is 276 × 118. 5 × 6 cm (UPPSC photo) is 394 × 472. 6 × 3 cm (UPPSC signature) is 472 × 236. At 300 DPI, 3.5 × 4.5 cm is 413 × 531 pixels, and at 100 DPI it's 138 × 177.
Why 275 × 354 appears everywhere
Many state portals ask for 275 × 354 pixels for photos and 275 × 118 for signatures. Those are simply 3.5 × 4.5 cm and 3.5 × 1.5 cm at 200 DPI, rounded down by one pixel. If your form gives both, match the pixels exactly; the one-pixel difference in cm doesn't matter.
The DPI inside the file
A JPG can record its DPI in its header. Some portals read it to work out the size in cm, so a correct 276 × 354 photo marked 72 DPI can appear as 9.7 × 12.5 cm. FitMyKB writes the DPI you choose into the file, without re-compressing it.
Resize in cm here
Set the unit to cm, type the width and height from your notice and the DPI, and the tool works out the pixels, crops to the right shape and records the DPI.
Questions
What DPI should I use if the form doesn't say?
200 DPI is the usual choice for Indian exam forms; for printing, use 300.
Does a higher DPI make the photo better?
Not on its own. It only changes how many pixels the same centimetres need; the file gets bigger in KB too.
Related tools
Resize an image in cmSet the size in centimetres, millimetres or inches and a DPI, just as forms and print shops ask.
Exam photo & signature resizer for govt examsPick your exam and get a form-ready photo, signature, thumb or declaration in one step: exact size, KB range, DPI, name and date.
Passport size photoCrop any photo to the standard 35 × 45 mm passport shape, then compress it for online forms.