Poster Print Sizes and Ratios: A Wall Art Cheat Sheet

Standard US poster print sizes are 8 × 10, 11 × 14, 12 × 16, 12 × 18, 16 × 20, 18 × 24 and 24 × 36 inches, while the UK and Europe mostly use A sizes (A4 to A0) and metric sizes such as 30 × 40 and 50 × 70 cm. At 300 DPI, a 12 × 18 poster needs 3600 × 5400 pixels, 18 × 24 needs 5400 × 7200 and 24 × 36 needs 7200 × 10800.

Those sizes fall into a handful of aspect ratios, and the ratio, not the size, decides whether one design can fill them all. This cheat sheet gives every common size in inches, millimeters and pixels, groups them by ratio, and shows how to set up print files that crop cleanly to everything you sell.

Standard poster sizes grouped by ratio

An aspect ratio is simply width divided by height. Every size in the same row below has the same shape, so a file made for one scales up or down to the others with no cropping.

Gelato’s poster guide makes a useful point for sellers who ship internationally: 30 × 40 cm, 50 × 70 cm and 70 × 100 cm have matching frames widely available and keep the same ratio as 12 × 16, 20 × 28 and 28 × 40 inches, so the design doesn’t shift when an order converts between centimeters and inches. It also notes that A sizes can make frame shopping harder for some buyers. Read its poster selling guide for the full list of papers and formats.

US poster sizes in pixels at 300 and 150 DPI

300 DPI is the target for anything viewed up close; around 150 DPI is the practical floor for larger posters seen from a few feet away.

A sizes and metric poster sizes in pixels

If most of your buyers are in the UK or Europe, A sizes and metric frames are what they already own. Our guide to print-on-demand in the UK covers the providers that print locally.

What DPI does a poster really need?

Gelato’s poster guidance sums it up: aim for at least 150 DPI at the final print size, with 300 DPI ideal. The reason large posters get away with less is distance. A small print is read from arm’s length, while a 24 × 36 poster is usually seen from across a room, where the eye can’t pick out the extra detail.

The problem is the pixel count. A 4096-pixel image, sold as “4K,” prints at about 114 DPI along the 36-inch side of a 24 × 36 poster. It’s fine at 16 × 24 (about 171 DPI on the long side) and comfortable at 12 × 18 (about 228). For bigger sizes you need a larger original, a careful upscale or a vector design. See how to upscale an image for print and when to vectorize instead; the underlying math is explained in the t-shirt size and DPI guide.

Which aspect ratio should you design in?

If you only sell one ratio family, design at the largest size in it and scale down: a 7200 × 10800 master covers every 2:3 size from 4 × 6 to 24 × 36. If you want to offer several ratios from one piece of art, start from 2:3 (the tallest common shape) and crop down to the others. Here’s what each crop costs you from a 7200 × 10800 master:

The rule that makes this work: keep every important element inside the central 83% of the master’s height (the 4:5 crop), and let only background, sky or pattern run into the top and bottom bands. Leave generous margins on text so it never sits hard against a trimmed edge.

Bleed, trim, frames and canvas wraps

Bleed is extra artwork beyond the trim line, so a slightly off cut never leaves a white sliver. How much you need depends on the product and even the print partner:

• Frames hide the edges. The lip of a frame covers a few millimeters on every side, and a mat covers more. Keep signatures, text and key details well inside the edge on anything sold framed.
• Canvas wraps fold. On a gallery wrap, the outer band of the file turns around the frame sides. Put nothing important there, or choose a mirrored or solid-color edge if the provider offers it.
• Follow the template. Gelato’s product templates include bleed even though its catalog dimensions don’t, as its formats article explains. That’s typical: templates tell you more than size charts.

Sizes to offer in one listing

On Etsy, size is usually a variation within one listing, so build each listing around one ratio family. It keeps every variant true to the design and makes your size chart honest. A simple structure:

• US-focused 2:3 listing: 12 × 18, 16 × 24, 20 × 30 and 24 × 36.
• US-focused 3:4 listing: 12 × 16, 18 × 24 and 30 × 40, with 9 × 12 as a small option.
• UK and EU listing: A4, A3, A2 and A1, or 30 × 40, 50 × 70 and 70 × 100 cm with frames.
• Sets of three: one ratio and one margin style across all three prints, so they hang as a matched set.

Your photos should show scale: a room mockup at the real size and a simple size-comparison image. Our Etsy mockup checklist covers the rest, and the print-on-demand wall art guide covers products, providers and margins.

Poster file checklist

• The file’s ratio matches the listing’s size family, with a separate crop for every other ratio.
• Pixel dimensions match the provider’s template, including any bleed.
• Effective resolution is 300 DPI for small prints and no lower than about 150 DPI for large ones.
• Text and key details sit well inside the edges, clear of frames, mats and canvas wraps.
• Orientation matches the product: vertical and horizontal posters are often separate options.
• Colors are checked on a sample, especially for soft pastels or deep blacks.

Choosing where to print? Our Gelato review and Prodigi review compare two providers built around wall art.