Printing · 7 min read
The one table you actually need
Print sizes are written in inches in most photo labs and in centimetres on most Indian government forms. The confusion starts when a lab says 4x6 and a form says 10 by 15 cm. They are the same size, rounded. Use the table below to convert without guessing.
The pixel column assumes 300 DPI, which is the standard for a sharp print. At 200 DPI you can use two-thirds of those pixels and most people will not notice at normal viewing distance.
| Name | Inches | cm | Pixels at 300 DPI | Typical use |
|---|---|---|---|---|
| Stamp | 2 x 2 | 5.1 x 5.1 | 600 x 600 | Forms, ID stickers |
| Passport | 1.38 x 1.77 | 3.5 x 4.5 | 413 x 531 | Passport, visa, PAN |
| Small print | 4 x 6 | 10.2 x 15.2 | 1200 x 1800 | Album, wallet |
| Medium print | 5 x 7 | 12.7 x 17.8 | 1500 x 2100 | Frames, gifts |
| Large print | 6 x 8 | 15.2 x 20.3 | 1800 x 2400 | Wall frames |
| Portrait print | 8 x 10 | 20.3 x 25.4 | 2400 x 3000 | Large frames |
| A4 | 8.27 x 11.69 | 21 x 29.7 | 2480 x 3508 | Documents, posters |
Why your 4x6 print has white borders
A 4x6 print is a 2:3 ratio. A phone photo is usually 4:3. If the lab prints a 4:3 photo on 2:3 paper without cropping, it either adds white bars or stretches the image. Neither is what you wanted.
The fix is to crop the photo to 2:3 before sending it. In a resizer, set the output to 1200 by 1800 pixels and crop to fill. The lab then has nothing to adjust, and the print comes out edge to edge.
DPI does not change the pixels, it changes the print size
A common misunderstanding is that changing the DPI number makes a photo sharper. It does not. DPI is metadata that tells the printer how densely to pack the existing pixels. A 1200 by 1800 image printed at 300 DPI is 4 by 6 inches. The same image printed at 150 DPI is 8 by 12 inches and looks softer because each pixel is bigger.
So the question is never what DPI should I set. The question is how many pixels do I have, and how large will I print. If you need a 4x6 print, you need 1200 by 1800 pixels, whatever the DPI field says.
Passport and visa sizes are not the same everywhere
Indian passport photos are 3.5 by 4.5 cm with a white background. US passport photos are 2 by 2 inches. Schengen visa photos are 3.5 by 4.5 cm but with stricter head-size rules. A photo that passes for one country can be rejected for another even though the dimensions look similar.
Check the head size, not just the frame size. In most passport standards the head should occupy 70 to 80 percent of the photo height. That is why a photo cropped to the right centimetres can still be rejected.
Preparing a print-ready file
Start from the largest original you have. Cropping a small image up to 1200 by 1800 pixels will look soft. If the original is a phone photo of 3000 by 4000 pixels, you have plenty of room to crop and still keep 300 DPI.
Save as JPG at quality 90 to 95 for printing. Do not compress a print file to 50 KB; that is for upload forms, not for a lab. A print file of 1 to 3 MB is normal and correct.
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Questions people ask about this
What is 4x6 in cm?
4x6 inches is about 10.2 x 15.2 cm. At 300 DPI that is 1200 x 1800 pixels.
How many pixels is A4 at 300 DPI?
2480 x 3508 pixels.
Does DPI make a photo sharper?
No. DPI only tells the printer how large to print the existing pixels. Sharpness depends on pixel count.
What size is an Indian passport photo?
3.5 x 4.5 cm, which is 413 x 531 pixels at 300 DPI, with a white background.