Poster setup reference

Poster Pixel Dimensions at 150 and 300 PPI

Use the tables to set a poster canvas or check an existing image. The numbers are before bleed; add the printer's required bleed after choosing the trim size.

Exact formulasInch and A-series sizesNo sign-up

Quick answer: common poster sizes

12 × 18 in1800 × 2700 px at 150 PPI · 3600 × 5400 px at 300 PPI
18 × 24 in2700 × 3600 px at 150 PPI · 5400 × 7200 px at 300 PPI
20 × 30 in3000 × 4500 px at 150 PPI · 6000 × 9000 px at 300 PPI
24 × 36 in3600 × 5400 px at 150 PPI · 7200 × 10800 px at 300 PPI

The formula is direct: pixels = inches × PPI. A 24-inch edge at 300 PPI therefore needs 7200 pixels.

Check an image against these poster sizes

A-series poster pixels

A-series dimensions are converted from millimeters and rounded to the nearest whole pixel. ISO 216 defines the trimmed A-series paper sizes; bleed is not part of the trim size.

A4 · 210 × 297mm1240 × 1754 px at 150 PPI · 2480 × 3508 px at 300 PPI
A3 · 297 × 420mm1754 × 2480 px at 150 PPI · 3508 × 4961 px at 300 PPI
A2 · 420 × 594mm2480 × 3508 px at 150 PPI · 4961 × 7016 px at 300 PPI
A1 · 594 × 841mm3508 × 4967 px at 150 PPI · 7016 × 9933 px at 300 PPI
A0 · 841 × 1189mm4967 × 7022 px at 150 PPI · 9933 × 14043 px at 300 PPI

Size reference: ISO 216:2007 ↗. The printing company’s supplied template overrides a general table.

Choose 150 or 300 PPI

  • 300 PPI: use when the poster will be inspected close up, contains small text, or the provider explicitly asks for it.
  • 150 PPI: can work for larger photographic posters viewed from farther away, provided the printer accepts it.
  • Between the two: keep the original pixels and calculate the actual effective PPI. Do not resample only to make the metadata say 300.

Adobe distinguishes image PPI from printer DPI and notes that lower image resolution can still work for large-format prints viewed from a distance. Image quality, sharpening, paper, and the printer's workflow still affect the result.

Adobe print-resolution guidance ↗

Check the aspect ratio before export

Pixel count alone does not guarantee a clean fit. An 18 × 24 poster has a 3:4 ratio. A 24 × 36 poster has a 2:3 ratio. Moving the same 3:2 photograph from 24 × 36 to 18 × 24 requires cropping the long edge or adding borders.

  1. Choose the final trim size.
  2. Crop the artwork to the matching ratio.
  3. Check effective PPI after cropping, because cropping removes pixels.
  4. Add bleed only after the trim and crop are final.
  5. Keep small text, logos, and QR codes inside the printer's safe area.

Use the Print Bleed Calculator to calculate the final canvas when bleed is required.

Frequently asked questions

How many pixels are needed for an 18 × 24 poster?

Use 2700 × 3600 pixels at 150 PPI or 5400 × 7200 pixels at 300 PPI.

How many pixels are needed for a 24 × 36 poster?

Use 3600 × 5400 pixels at 150 PPI or 7200 × 10800 pixels at 300 PPI.

Should bleed be included in these numbers?

No. These are trim-size values. Add the exact bleed requested by the printer to every required edge.

Reviewed: August 15, 2026.