How to Choose the Correct Poster Size – A0 to A4 Explained in mm, cm & Inches

One of the most common questions our customers ask at Digraphics is: “Which poster size do I actually need?” It sounds simple, but choosing the wrong size is one of the most avoidable print mistakes — and it can mean wasting money on a poster that is too small to read from a distance, or too large for the wall it is going on. This complete guide explains every standard poster size from A0 to A4, gives you the exact dimensions in millimetres, centimetres, and inches, and tells you exactly which size to choose for every use case — so you order with complete confidence every time.

Understanding the ISO A Series Paper Standard

All standard poster sizes — A0, A1, A2, A3, A4 — belong to the ISO 216 international paper standard, which is used throughout the UK, Europe, and most of the world. The system is elegantly logical: each size is exactly half the area of the size above it, and the aspect ratio (the proportion of width to height) remains constant at 1:√2 (approximately 1:1.414) throughout the entire series.

This means an A1 poster is exactly two A2 posters side by side. An A2 is exactly two A3 posters. And so on down the series. This consistency makes the series extremely practical for scaling designs up or down between sizes without distortion.

The sizes run from A0 (the largest standard paper format) down to A10 (roughly the size of a postage stamp). For poster printing, the relevant range is A0 through to A4.

A0 Poster Size – The Largest Standard Format

A0 is the largest standard ISO poster size — almost a full metre wide and nearly 1.2 metres tall. Its surface area is exactly 1 square metre, and every other A-series size is derived from it by halving.

When to Choose A0

• 🏪 Large retail environments — window displays, atrium banners, and entrance posters where maximum visual impact is needed from a distance
• 🏛️ Exhibitions and trade shows — display stands, pop-up backgrounds, and feature wall graphics
• 🎙️ Concert and event promotion — venue lobby posters, backstage signage, and outdoor event hoardings
• 🏥 Hospital and healthcare facilities — wayfinding posters and public health information displays in large spaces
• 🏫 Schools, colleges, and universities — corridor displays, assembly hall notices, and large-format educational posters
• 🏙️ Planning and architectural drawings — site plans, maps, and technical drawings at full scale

Key Point About A0

Because A0 is so large, it is essential that your artwork is supplied at high resolution — ideally 150 dpi at full size, or 300 dpi at 50% of final size. Low-resolution artwork that looks fine on screen will print blurry and pixelated at A0. If you are unsure about your file, WhatsApp it to us before ordering and our team will assess it for free.

🛒 Order A0 Posters from £45 — satin, waterproof PVC, self-adhesive vinyl, and more. Also available as our A0 PVC Waterproof Poster from £59 for outdoor use.

A1 Poster Size – The Exhibition & Retail Standard

A1 is half the size of A0 — and the most popular size for professional exhibition posters, retail window displays, and indoor promotional signage. It is large enough to be read comfortably from several metres away, while remaining practical to produce, transport, and display in standard poster frames and exhibition stands.

When to Choose A1

• 🎪 Exhibition and conference posters — the standard size for academic posters at conferences, and for display panels at trade shows and exhibitions
• 🏪 Retail window and interior displays — visible from the pavement, impactful inside a store
• 🎉 Event promotion — gig posters, club night flyers scaled up, and venue promotional material
• 🏢 Office and workplace signage — health and safety notices, team announcements, and internal brand campaigns
• 🏙️ Estate agent window boards — A1 is a standard estate agency display format across the UK
• 🏋️ Gym and fitness studios — class timetables, membership offers, and motivational wall art

A1 vs A0: Which Should I Choose?

Choose A1 when your poster will be displayed indoors at a distance of up to 3–5 metres, in a standard poster frame, or in a retail window. Choose A0 when the display space is very large, the viewing distance is greater than 5 metres, or you need maximum visual dominance in a space.

🛒 Order A1 Posters from £25 — satin, waterproof PVC, self-adhesive vinyl, and more. Also available as A1 Gloss Poster from £25 and A1 Outdoor Waterproof PVC from £46.

A2 Poster Size – The Versatile Mid-Range Format

A2 is half the size of A1 — and arguably the most versatile poster size in the standard range. It is large enough to be clearly readable from across a room, but compact enough to fit in almost any indoor environment without overwhelming the space. A2 is the go-to format for businesses that want visible, professional poster signage without committing to the full scale of an A1.

When to Choose A2

• 🏨 Hotel lobbies and reception areas — promotional posters and welcome signage
• 💇 Salons and beauty businesses — service menus, price lists, and promotional offers in client-facing areas
• 🍽️ Restaurant and café interiors — menu boards, daily specials, and branded wall art
• 🏫 Classroom displays — educational posters that need to be readable from the back of a standard-sized classroom
• 🏙️ Public transport information — bus stop notices, community board announcements
• 🎙️ Music and entertainment promotion — gig and event posters for placement in venues and music shops

A2 vs A1: Which Should I Choose?

Choose A2 when your poster is for a smaller interior space where an A1 would feel too dominant, when you are placing multiple posters side by side, or when budget is a consideration. A2 prints at a lower cost per unit than A1 while still delivering strong visual presence.

🛒 Order A2 Posters from £20 — satin, waterproof PVC, self-adhesive vinyl, and more. Also available as A2 Matt Poster from £18 and A2 Outdoor Waterproof PVC from £39.

A3 Poster Size – The Office & Retail Workhorse

A3 is half the size of A2 and exactly twice the size of a standard A4 sheet. It is the most widely used poster size for indoor notices, information displays, and point-of-sale signage across offices, retail environments, and community spaces throughout the UK. The A3 format strikes the ideal balance between visibility and practicality — large enough to be noticed, small enough to go almost anywhere.

When to Choose A3

• 🏢 Office noticeboards — the single most common format for workplace notices and internal communications
• 🛒 Point-of-sale displays — counter-top stands, till-side promotions, and shelf-edge signage
• 🎕 Café and restaurant menus — table-top or wall-mounted specials boards
• 🏭 Market stalls and pop-up shops — product information, price lists, and brand displays on a table or folding stand
• 👅 Fashion and retail displays — promotion signage and new arrival notices
• 🏫 School and community noticeboards — the standard size for notice boards in most UK institutions

A3 vs A2: Which Should I Choose?

Choose A3 when the poster will be read at close range (within 1–2 metres), when the display space is limited, or when you need to produce multiple copies cost-effectively. Choose A2 when the poster needs to be readable from across a room or when you want more design space for imagery and typography.

🛒 Order A3 Posters from £15 — satin, waterproof PVC, self-adhesive vinyl, and more. Also available as A3 Gloss Poster from £16 and A3 Matt Poster from £16.

A4 Poster Size – The Most Familiar Format

A4 is the standard UK office paper size — the sheet that goes in your printer at home or work. As a poster format, A4 is best suited for close-reading applications: pinned notices, counter-top information sheets, window stickers, and promotional inserts. It is the smallest practical poster size and is typically used when wall or display space is very limited, or when the content will be read at a distance of less than one metre.

When to Choose A4

• 📌 Counter-top promotional inserts — placed face-up on a counter or desk for customers to pick up and read
• 🔗 Noticeboard inserts — pinned on a crowded noticeboard alongside other A4 notices
• 🚗 Car window notices — for-sale signs, parking information, and vehicle rental details
• 🏠 Residential notices — property letting, window advertising, and local community announcements
• 📸 Photography and art prints — smaller decorative prints for home or office display in A4 frames

A4 vs A3: Which Should I Choose?

Choose A4 only when the poster will be read at very close range or when the display space genuinely cannot accommodate A3. For almost every public-facing application — shops, restaurants, offices, community spaces — A3 is the minimum practical size for a poster that is meant to be noticed.

🛒 Order A4 Posters from £15 — available in satin, waterproof PVC, self-adhesive vinyl, grey back, and more via our Large Format Poster range.

Complete Poster Size Comparison – A0 to A4 at a Glance

Here is a quick-reference table of all standard poster sizes with their exact dimensions in millimetres, centimetres, and inches:

How to Choose the Right Poster Size – Step by Step

Use these four questions to determine the right size for your poster every time:

Step 1 – Where Will the Poster Be Displayed?

This is the most important factor. Consider the physical space the poster will occupy and how it will be mounted or displayed:

• Large open space, high ceiling, wide wall — A0 or A1
• Standard retail or office interior — A1 or A2
• Counter, desk, or small wall space — A3 or A4
• Standard poster frame or noticeboard — check the frame size and match it exactly

Step 2 – From What Distance Will It Be Read?

A rough guide to minimum readable poster sizes at different viewing distances:

• Within 1 metre — A4 or A3
• 1–3 metres — A3 or A2
• 3–6 metres — A2 or A1
• 6+ metres — A1 or A0

Step 3 – How Much Content Are You Including?

More content needs more space. A poster with a single bold headline and a QR code can work at A4. A poster with a headline, body text, multiple images, contact details, and a logo needs A3 at minimum — and probably A2 or larger if you want it to be visually balanced.

Step 4 – Indoor or Outdoor?

For outdoor use, standard paper posters will not survive rain, wind, or UV exposure. You need our waterproof PVC poster range — printed on 440gsm PVC with UV-resistant inks. Available in A2 from £39, A1 from £46, and A0 from £59. For indoor display, our satin, gloss, and matt paper poster ranges are perfect.

Artwork Resolution Guide by Poster Size

Supplying your artwork at the correct resolution prevents blurry, pixelated prints. Here is what we recommend for each size:

• 📌 A4 poster — minimum 300 dpi at full size
• 📌 A3 poster — minimum 300 dpi at full size (or 150 dpi for image-only designs viewed at distance)
• 📌 A2 poster — minimum 150 dpi at full size
• 📌 A1 poster — minimum 150 dpi at full size (72 dpi is not acceptable at A1)
• 📌 A0 poster — minimum 100–150 dpi at full size. For vector-based designs (logos, text, graphics), resolution is not a concern — vector files scale perfectly to any size.

If you are not sure whether your artwork meets the resolution requirement for your chosen size, WhatsApp us the file before ordering and we will assess it for free and tell you honestly whether it will print well.

Which Paper Stock Should I Choose for My Poster?

Once you have chosen your size, you need to choose a paper or material stock. Here is a summary of what we offer and when to use each:

• 🖼️ Satin / Silk (150–240gsm) — the most popular indoor poster stock. A subtle sheen that reproduces colours vividly without the high glare of gloss. Available for all sizes from A4 to A0.
• ✨ Gloss (210–260gsm) — a high-shine finish that makes photographic imagery pop. Best for photo posters, promotional displays, and any design with strong visual content. Available via our Gloss Poster collection.
• 🌫️ Matt (210gsm) — a non-reflective finish that eliminates glare and gives a professional, considered aesthetic. Ideal for text-heavy posters, educational content, and environments with strong lighting. Available via our Matt Poster collection.
• 🌧️ Waterproof PVC (440gsm) — essential for any outdoor application. UV-resistant inks, durable PVC substrate, and fully waterproof construction. Available in A2, A1, and A0 via our PVC Poster collection.
• 🎟️ Self-Adhesive Vinyl — peels and sticks to any smooth, clean surface. Ideal for window displays, wall graphics, van livery, and any application where the poster needs to adhere rather than hang. Available for all sizes via our Large Format Poster range.
• ⬛ Grey Back (Blackout) — a double-sided opaque material that blocks light transmission completely. Used for window displays where you do not want the poster to be see-through from behind.

Quick-Decision Poster Size Guide by Business Type

Not sure where to start? Here is what we most commonly recommend for specific businesses and use cases:

• 🍕 Restaurants and takeaways — A3 for counter displays; A2 for window posters; A1 for exterior-facing window graphics
• 🏪 Retail shops — A2 or A1 for window displays; A3 for in-store POS; A0 for flagship entrance displays
• 🏋️ Gyms and fitness studios — A2 or A1 for membership and class posters; A3 for reception notice boards
• 🎪 Events and concerts — A1 for venue lobby; A0 for entrance or outdoor hoarding; A3 for inside-venue information
• 🏥 Healthcare and clinics — A2 or A3 for waiting room displays; A1 for entrance area signage
• 🏢 Offices — A3 for noticeboards; A2 or A1 for reception and lobby signage
• 🏫 Schools and education — A3 for classroom displays; A2 or A1 for corridor and hall posters; A0 for assembly hall or main entrance

Order Your Poster From Digraphics – Wembley

Now that you know exactly which size you need, ordering from Digraphics is straightforward. Every poster order includes a free artwork check before printing, free UK delivery, and the personal service of a Wembley-based print studio you can reach directly on WhatsApp throughout the process.

Frequently Asked Questions – Poster Size Guide

What is the most popular poster size in the UK?

The most ordered poster size in the UK for business and promotional use is A1 (594×841mm / 59.4×84.1cm). It balances strong visual impact with practical handling and fits standard display frames widely available in the UK. For office and retail notices, A3 (297×420mm) is the most common.

Is A0 twice the size of A1?

Yes — exactly. A0 (841×1,189mm) is twice the area of A1 (594×841mm). This relationship holds throughout the entire ISO A series: each size is exactly twice the area of the size below it. A1 is twice A2, A2 is twice A3, and A3 is twice A4.

What resolution do I need for an A0 poster?

For an A0 poster, supply your artwork at a minimum of 100–150 dpi at full size. For a design that uses vector graphics (logos, text, geometric shapes created in Illustrator or similar), resolution is not a concern — vectors scale to any size without loss of quality. If you are working from photographs, ensure they are at least 150 dpi at A0 dimensions.

Can I get outdoor waterproof posters at all sizes?

Yes — our waterproof PVC poster range is available in A2 (from £39), A1 (from £46), and A0 (from £59). All are printed on 440gsm PVC with UV-resistant inks, fully waterproof and suitable for outdoor display.

What is the difference between A3 and A4?

A3 (297×420mm / 29.7×42.0cm) is exactly twice the size of A4 (210×297mm / 21.0×29.7cm). An A3 sheet folded in half is precisely an A4 sheet. For poster use, A3 is significantly more visible and impactful than A4 — for any public-facing display, A3 is the minimum we recommend.

Do I need to add a bleed to my poster artwork?

Yes — all poster artwork should include a 3mm bleed on all four sides beyond the final trim size. This prevents white edges appearing after trimming. So for an A3 poster (297×420mm), your artwork file should be 303×426mm. If you are unsure about bleed, WhatsApp us your file and we will check it before printing.