How Big Is a Standard Poster in the UK? Dimensions & Printing Guide

INTRODUCTION

If you’re planning a poster whether for marketing, events, or decoration one of the first questions is:

👉 How big should it be?

Here’s the twist most people don’t realise:

Poster sizes in the UK follow the international A-series standard, but there are slight variations depending on the printer, purpose, or frame.

Choosing the wrong size can make your design look awkward or even cost more to print. Let’s break down the standard UK poster sizes so you know exactly what to order.

Standard Poster Sizes in the UK

The most commonly used poster sizes in the UK are based on the A-series (ISO 216 standard):

Poster Size	Dimensions (mm)	Dimensions (inches)	Typical Use
A3	297 x 420 mm	11.7 x 16.5 in	Small posters, offices, noticeboards
A2	420 x 594 mm	16.5 x 23.4 in	Medium posters, shops, events
A1	594 x 841 mm	23.4 x 33.1 in	Large posters, exhibitions, promotions
A0	841 x 1189 mm	33.1 x 46.8 in	Very large posters, trade shows, billboards

Tip: The bigger the poster, the further away your audience can be and still read it clearly.

Other Common Poster Sizes in the UK

Sometimes, printers offer non-A-series or custom sizes for specific uses:

• B-series posters – slightly larger than A-series, often used for outdoor promotions
• Square posters – e.g., 500 x 500 mm for social media-style prints or interior decoration
• Custom dimensions – tailored for specific frames or events

Choosing the Right Poster Size

When picking a size, consider:

1. Viewing Distance – larger posters for long-distance visibility
2. Location – small posters fit noticeboards, big posters for walls or windows
3. Content – more text or images requires a bigger poster
4. Budget – larger posters cost more to print and ship

Tips for Designing Posters by Size

• A3: Keep text larger than 14pt for readability
• A2: Headings 36–48pt, subheadings 24–36pt
• A1/A0: Use bold, simple fonts; avoid overcrowding
• Maintain hierarchy – titles, subtitles, and body text must stand out

Pro Tip: Always design your poster at actual size (100% scale) to avoid scaling issues when printing.

Final Thoughts

In the UK, the standard poster sizes are A3, A2, A1, and A0 following international A-series dimensions.

Choosing the right size ensures your poster:

• Looks professional
• Fits its intended location
• Communicates your message clearly

For marketing or event posters, it’s not just about size it’s also about readability, design, and printing quality.

👉 Ready to print high-quality posters in the perfect UK size? Contact Social Media Max today. Don’t wait your competitors won’t.