The short version
- Poster design is about being understood at a distance in a few seconds, so every poster needs one dominant headline and a background that points to it.
- A strong poster has three levels of information: the headline, the key facts such as date and place, and the details.
- At 300 dpi, an A4 poster is 2480 by 3508 pixels, A3 is 3508 by 4961, and an 18 by 24 inch poster is 5400 by 7200.
- Print designs need bleed, extra background beyond the trim edge, usually 3 mm in Europe or 0.125 inches in the US.
- Bold, simple backgrounds with a clear light area behind the headline read far better at distance than detailed images.
On this page
Good poster design works at a distance and at a glance: one dominant headline, a few key facts, and a background that guides the eye straight to the words. The background matters more than people expect. A bold field of colour with a clear, calm area behind the headline reads from across a room; a detailed photo or busy pattern makes people stop and search, and most won't. Build the background to carry the headline, then add the facts in a clear order.
This guide covers hierarchy, print sizes, bleed and backgrounds that work in print. For printing gradients without stripes or mud, see printing gradients; for the broader event look, see event branding.
Poster hierarchy: three levels of information
Most posters fail by giving everything equal weight. Decide the three levels before you design, and make each clearly bigger or bolder than the next. The headline should be readable from the furthest point someone will see the poster; the key facts from a few steps closer; the details only up close.
| Level | What it holds | How it looks |
|---|---|---|
| 1. Headline | The name or the promise, in a few words | The largest element by far |
| 2. Key facts | Date, time, place, price if relevant, or the one action | Clearly smaller, still bold |
| 3. Details | Line-up, address, website, sponsors, small print | Small, grouped, out of the way |
A4 event poster: one headline, one line of key facts, the details below.
A3 announcement poster: the background's light sits behind the headline.
Poster sizes and pixels at 300 dpi
Print needs far more pixels than screens. Design at 300 dots per inch at the final size, or as vector artwork, so type and edges stay crisp. These are the common sizes and their pixel dimensions at 300 dpi.
A5 flyer
1748 × 2480
A4 poster
2480 × 3508
A3 poster
3508 × 4961
US Letter
2550 × 3300
18×24 in poster
5400 × 7200
| Size | Pixels at 300 dpi | Typical use |
|---|---|---|
| A5 | 1748 × 2480 | Flyers, handouts, counter cards |
| A4 | 2480 × 3508 | Noticeboards, windows, office walls |
| A3 | 3508 × 4961 | Shop windows, cafés, event venues |
| US Letter | 2550 × 3300 | Noticeboards and flyers in North America |
| 18 × 24 in | 5400 × 7200 | Street posters, gig posters, larger walls |
Designing a poster background that carries the headline
The background's job is to point. Put its lightest, calmest area (or darkest, for light type) behind the headline, and let colour and detail build towards the edges. The eye goes to the strongest contrast first, so make sure that is the headline, not a glow in the corner or a busy patch of photo.
Avoid
- A detailed photo behind the headline
- The brightest point of the background in a corner
- Five things at the same size
- Thin type on a mid-tone background
Do
- A bold, simple field with a calm zone
- The strongest contrast behind the headline
- One headline, clearly dominant
- Heavy type with strong light-dark contrast
Testing a poster for distance
You can't judge a poster at 100 percent zoom on a laptop. Zoom out until the poster is about the size it will look from across the room, or print it small and pin it on a wall, then step back. If you can't read the headline and tell what it is about in a few seconds, simplify: fewer words, a bigger headline, a calmer background.
- 1
Write the three levels
Headline, key facts, details. Cut anything that fits none of them.
- 2
Choose the size first
Set the canvas at the final size at 300 dpi, plus bleed.
- 3
Build the background
Bold colour, a calm zone for the headline, contrast building to the edges.
- 4
Set the headline big
Larger than feels comfortable. A strong display font helps.
- 5
Test at distance
Zoom out or print small, step back, and read it in three seconds.
- 6
Prepare for print
Check colours in CMYK, export as PDF or high-quality image with bleed, and ask for a proof.
Gradiently includes the print sizes above at 300 dpi, from A5 flyers to 18 by 24 inch posters, and a Mark moves its calmest region behind your headline automatically. Copy to sizes turns a finished poster into matching social posts and stories for the same event.
Questions people ask
What size should a poster be in pixels?
At 300 dpi, A4 is 2480 by 3508 pixels, A3 is 3508 by 4961, US Letter is 2550 by 3300, and an 18 by 24 inch poster is 5400 by 7200.
What makes a good poster design?
One dominant headline, a clear order of information, and a bold, simple background that directs attention to the words, readable in a few seconds from a distance.
What is bleed on a poster?
Extra background beyond the trim edge, usually 3 mm per side in Europe or 0.125 inches in the US, so no white edge appears when the poster is cut.
Can I use a gradient background on a printed poster?
Yes. Check how the colours convert to CMYK, avoid very subtle dark blends that can band, and ask the printer for a proof.
Written by Gradiently
The team behind Gradiently, a design tool built around Marks: living gradients that make everything you design look like yours.
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