Photo Print Sizes: Ratios, Pixels and Frame Fit
Choose a photo print by its aspect ratio as well as its inch dimensions. A file can contain enough pixels and still lose part of the picture when fitted to a differently shaped frame.
| Ratio, short:long | Pixels at a chosen 300 PPI | |
|---|---|---|
| 4 × 6 in | 2:3 | 1200 × 1800 |
| 5 × 7 in | 5:7 | 1500 × 2100 |
| 8 × 10 in | 4:5 | 2400 × 3000 |
| 8.5 × 11 in | 17:22 | 2550 × 3300 |
Crop a 4:3 image for a 6 × 4 print
Start with a 4000 × 3000 pixel landscape image. A centred 3:2 crop using the full width would be about 4000 × 2667 pixels, so roughly 333 pixels of height must be removed in total. An exact 3600 × 2400 crop is another option if the subject allows trimming both dimensions. At 6 × 4 inches, that exact crop supplies 600 PPI. Choose the composition yourself before the printer makes an automatic crop.
Fit, fill and resampling do different jobs
Fit preserves the whole photo and can leave blank bands. Fill covers the print area by cropping part of the image. Resampling changes the number of pixels; it cannot restore detail that was absent from a blurry source. Printer DPI describes output dots, whereas image PPI relates source pixels to physical inches.
Prepare one print
- Check the frame opening and whether a mat will cover the edges. Keep faces and important details clear of the trim.
- Crop a copy to the desired ratio, retaining the original image.
- Calculate effective PPI at the final dimensions and inspect the image at a useful viewing size. A 300 PPI calculation is a planning choice, not a universal pass/fail test.
- Select matching photo paper and its supported media setting. Inspect the crop preview before printing a sample.
A 10 × 15 cm sheet is close, but different
An exact 4 × 6 inch sheet is 101.6 × 152.4 mm. A 100 × 150 mm sheet is smaller in both directions. Use the dimensions printed on the paper packet and supplied by the driver when edge-to-edge framing matters.
Sources and method
- NIST: SI units of length: the exact conversion of one inch to 25.4 millimetres. Inch and point values below are calculated from the stated nominal dimensions.
- Adobe: image resolution for printing: the relationship between image pixels, print dimensions and resolution. The worked examples are our own calculations.
- Adobe: standard photo sizes: common print formats and cropping considerations.