Poster-dimension helper
Work out the largest poster size you can print from an image while staying above a minimum acceptable quality — posters are viewed from further away, so they can use a lower DPI than a photo print.
Result
Maximum poster width
Maximum poster height
How to use this calculator
- Enter the image's pixel width and height.
- Set your minimum acceptable DPI — 150 is a common choice for posters viewed from a normal distance, lower for very large posters viewed from further away.
- Read the maximum poster size.
Assumptions
- Assumes the poster will be viewed from a normal poster-viewing distance (a few feet or more), not examined up close — a lower DPI is acceptable at that distance than for a hand-held photo.
Technical details: what the fields mean
- Image width
widthPx - The image's width in pixels.
- Image height
heightPx - The image's height in pixels.
- Minimum acceptable quality
minDpi - The lowest DPI you're willing to accept — posters viewed from a few feet away can look sharp at 100–150 DPI, well below the 300 DPI used for close-up photo prints.
Methodology
Maximum poster width = image width (px) ÷ minimum DPI. Maximum poster height = image height (px) ÷ minimum DPI.
Worked example
3000×2000px image at 150 DPI minimum
Inputs: widthPx=3000, heightPx=2000, minDpi=150
Result: 20.0in × 13.3in maximum
Practical guidance
- The larger and further away a poster will be viewed, the lower a DPI you can get away with — a billboard is printed at a tiny fraction of photo-print DPI and still looks sharp from the street.
Common mistakes
- Using a photo-print DPI standard (300) for a large poster, which unnecessarily limits the maximum size you could otherwise print the same image at.
FAQs
What DPI is OK for a poster?
100–150 DPI is commonly acceptable for a poster viewed from a normal distance of a few feet or more — much lower than the 300 DPI used for close-up photo prints.