Print Sizing Sheet
Print size is pixels over dpi. The dpi you need depends on how far away it will be seen.
BFCBrilliance · bfcbrilliance.com/tools/print-size-dpi-calculator
The arithmetic
- PRINT SIZE
- pixels ÷ dpi
- DPI NEEDED
- 3438 ÷ viewing distance in inches
- 12 in — hand held
- 287 dpi — where '300' comes from
- 3 ft away
- about 96 dpi
- 6 ft away
- about 48 dpi
- 10 ft away
- about 29 dpi
- 24 MP (6000 x 4000)
- 20 x 13.3 in at 300 dpi
- ⚠ Use the CLOSEST distance
- people walk up to things
- ⚠ Upscaling adds pixels
- not detail — softness just gets bigger
Prints to order
| Image | Pixels | MP | Size wanted | DPI it gives | OK? |
|---|---|---|---|---|---|
This print
- Image
- Date
- Pixel width
- Pixel height
- MEGAPIXELS
- Aspect ratio
- Target dpi
- MAX SIZE AT TARGET
- Viewing distance
- DPI NEEDED AT THAT DISTANCE
- MAX SIZE AT THAT DPI
- Crop needed?
- Ordered size
Before ordering a print
- Viewing distance decided — the CLOSEST anyone will get
- Crop decided BEFORE sizing, since cropping cuts the pixel count
- Aspect ratio checked against the frame or paper
- Bleed and border allowed for if the paper size is fixed
- Original file used, not a resized copy or a social media download
- Upscaling recognised for what it is if used at all
- Printer's dpi specification not confused with the file's ppi
- A small test strip printed first for anything expensive
300 dpi is an arm's-length answer
It comes from one arcminute of visual acuity at a 12 inch reading distance — 3438 ÷ 12 is 287, which the industry rounds up to 300. Applied to a large print it is simply wasteful: at ten feet the same arithmetic asks for 29 dpi, and a 24 megapixel file would cover seventeen feet of width. Billboards are printed in single digits because nobody is ever close to one.
The distance has to be genuinely fixed
Low-resolution maths only holds where nobody can walk closer — a billboard by a road, a sign above a door. A gallery print or a hallway poster WILL be inspected from a foot away by somebody curious, and then the figure that justified 40 dpi protects nothing. Use the closest realistic distance, never the intended one.