Resolution and size for print files
Key points
- Print photos usually aim for 300 dpi
- Pixels = size (in) × 300
- Send logos as vectors and stop worrying
An image that looks sharp on screen often prints blurry. Screens and paper measure size differently. Knowing a few units makes it easy to work out the size you need.
Units to know
| Unit | Meaning |
|---|---|
| px | Pixel: one dot in a raster image |
| in | Inch: 25.4 mm |
| pt | Point: 1/72 inch, about 0.353 mm. The base unit in print and PDF |
| dpi | Dots per inch: print resolution |
Calculating the pixels you need
Photos for print usually target 300 dpi. The formula is simple:
pixels needed = print size (mm) ÷ 25.4 × 300
pixels needed = print size (in) × 300A photo filling an A4 page (210 × 297 mm) needs 210 ÷ 25.4 × 300 ≈ 2480 by 297 ÷ 25.4 × 300 ≈ 3508, so about 2480 × 3508 pixels. US Letter (8.5 × 11 in) needs 2550 × 3300. A business card (3.5 × 2 in) needs 1050 × 600.
Banners and posters seen from a distance are often fine at 150 dpi or less. Printers have their own recommendations, so ask in advance.
Vectors don't need to worry
Logos, text and shapes sent as vectors (SVG, EPS, PDF) never need resolution calculations. They are drawn at whatever size they are printed, so they are always sharp. That is why print shops often ask for logos as vector files. If you have an SVG, convert it to EPS or PDF.
Sizes on this site
When converting SVG to EPS or PDF, 1 px in the SVG becomes 1 pt. A 600 px wide SVG becomes 600 pt wide, about 21.2 cm (8.3 in). Since it is a vector, scale it to whatever size you print.
Check the colors too
Screens mix color from three kinds of light (RGB), while printing uses four inks (CMYK). Very vivid blues and greens on screen may not print the same. If color matters, ask the printer whether they need CMYK files and change the color mode in your design app before saving.