💡 How to calculate paper size in pixels?
Physical paper (like A4 or US Letter) has fixed physical dimensions in millimeters or inches. Pixels, on the other hand, are digital dots with no absolute physical size. To bridge this gap, you need a resolution metric known as DPI (Dots Per Inch). The basic formula is: Width in Pixels = Physical Width (inches) × DPI. Height in Pixels = Physical Height (inches) × DPI.
🖨️ Why is 300 DPI the standard for printing?
While 72 or 96 DPI is usually sufficient for digital images displayed on monitors, professional printing requires much denser ink distribution. 300 DPI is the universally accepted standard for high-quality commercial printing (such as posters, flyers, and standard Letter/A4 documents). At this resolution, the human eye cannot discern individual pixel jaggedness. For example, a standard A4 sheet requires 2480 × 3508 pixels to maintain crisp quality at 300 DPI.
| Paper Size | 72 DPI (Web) | 150 DPI (Draft) | 300 DPI (Print) |
|---|---|---|---|
| Letter | 612 × 792 px | 1275 × 1650 px | 2550 × 3300 px |
| Legal | 612 × 1008 px | 1275 × 2100 px | 2550 × 4200 px |
| A3 | 842 × 1191 px | 1754 × 2480 px | 3508 × 4960 px |
| A4 | 595 × 842 px | 1240 × 1754 px | 2480 × 3508 px |
| A5 | 420 × 595 px | 874 × 1240 px | 1748 × 2480 px |