Print Size Calculator
Enter the pixel dimensions of your file and the resolution you are printing at, and this calculator returns the finished print size along with a verdict on how sharp it will look.
How to calculate print size from pixels
Divide each pixel dimension by the print resolution: inches = pixels ÷ DPI. A 2550 × 3300 pixel file at 300 DPI prints exactly 8.5 × 11 inches — a US Letter page.
Drop the resolution and the print grows. The same file at 150 DPI covers 17 × 22 inches, which is fine for a poster but visibly soft if you hold it close.
Worked with the values in the calculator above
width = 3,000 px ÷ 300 DPI = 10 in
height = 2,000 px ÷ 300 DPI = 6.6667 in
cm = 10 in × 2.54 = 25.4 cm Paper size to pixels
Letter size to pixels at 300 DPI is 2550 × 3300. A4 is 2480 × 3508 and Tabloid is 3300 × 5100. For poster size in pixels, a 24 × 36 inch print at 150 DPI needs 3600 × 5400, which a 20-megapixel camera covers comfortably.
If your file falls short, printing it slightly smaller is almost always better than resampling it larger.
Reference table
| Size | Inches | Millimetres | At 150 DPI | At 300 DPI |
|---|---|---|---|---|
| Photo 4 × 6 | 4 × 6 in | 102 × 152 mm | 600 × 900 | 1,200 × 1,800 |
| Photo 5 × 7 | 5 × 7 in | 127 × 178 mm | 750 × 1,050 | 1,500 × 2,100 |
| Photo 8 × 10 | 8 × 10 in | 203 × 254 mm | 1,200 × 1,500 | 2,400 × 3,000 |
| US Letter | 8.5 × 11 in | 216 × 279 mm | 1,275 × 1,650 | 2,550 × 3,300 |
| A4 | 8.27 × 11.69 in | 210 × 297 mm | 1,240 × 1,754 | 2,480 × 3,508 |
| A3 | 11.69 × 16.54 in | 297 × 420 mm | 1,754 × 2,480 | 3,508 × 4,961 |
| Tabloid | 11 × 17 in | 279 × 432 mm | 1,650 × 2,550 | 3,300 × 5,100 |
| Poster 18 × 24 | 18 × 24 in | 457 × 610 mm | 2,700 × 3,600 | 5,400 × 7,200 |
| Poster 24 × 36 | 24 × 36 in | 610 × 914 mm | 3,600 × 5,400 | 7,200 × 10,800 |
Frequently asked questions
How many pixels do I need for printing?
Multiply the print size in inches by 300 for photo quality. An 8 × 10 print needs 2400 × 3000 pixels; a 4 × 6 needs 1200 × 1800.
How do I work out pixels to inches for printing?
Work backwards from the print: pixels = inches × DPI. Use 300 DPI for anything held in the hand and 150 DPI for posters, so a 10 inch wide print needs 3000 or 1500 pixels respectively.
What size is 8.5 x 11 paper in pixels?
US Letter is 2550 × 3300 pixels at 300 DPI, 1275 × 1650 at 150 DPI and 816 × 1056 at 96 PPI.
How big can I print my photo?
Divide each pixel dimension by 300 for a hand-held print, or by 150 for a poster. A 6000 × 4000 file gives 20 × 13.3 inches at 300 DPI and twice that at 150.
What resolution should a poster be?
150 DPI is standard for posters viewed from a metre or more. Very large banners are routinely printed at 72 DPI or less because of the viewing distance.