DPI Calculator

300 ppi is the usual figure for a photographic print held at reading distance; large prints viewed from further away work at far less.
Used with the print length below to get the density of an existing print.
Pixel density
250.00 ppi
Image Size & Print Size Calculator
Print width
12.000 in
Print height
9.600 in
Print width
30.48 cm
Print height
24.38 cm
Megapixels
7.200 MP
Aspect ratio
5:4
Photos that fit on the card
2,560
Card capacity
64,000 MB
Worked out from Definition of pixel density: ppi = pixels / inches of print and 2 other sources.
Card capacity is decimal (1 GB = 1000 MB) as sold, and part of the card is taken by its file system, so the real photo count is a little lower. Raw file sizes also vary with scene detail.

How this is worked out

3 steps
  1. ppi = 1000 px / 4 in = 250 ppi.
  2. That is 7.2 megapixels at an aspect ratio of 5:4.
  3. Capacity: 64 GB = 64000 MB; floor(64000 / 25) = 2560 photos.

Results are general information, not financial, tax, legal, medical or engineering advice.