A0 vs A1: Which Size Should Your Conference Poster Be?

Quick answer: Use the size the conference asks for. If the rules allow either, choose A0 (841 × 1189 mm) when you have lots of data, images or a large board, and A1 (594 × 841 mm) when the board is small, the event is a poster competition or departmental day, or you need to carry the poster by hand. A0 is exactly twice the area of A1, so it gives you room for bigger text, not just more text.

A0 and A1 are the two sizes UK academics ask us about most. Both are standard ISO 216 paper sizes, both print well on our 260gsm papers, and both are used at real conferences. This guide explains the difference, what conference organisers usually ask for, and how to decide when the rules leave the choice to you.

A0 vs A1 at a glance

Under ISO 216, A0 has an area of one square metre and every A-size keeps the same 1:√2 shape, so A1 is simply A0 cut in half (Markus Kuhn, University of Cambridge). This is why a design made for A0 can be printed at A1 without stretching, although the text will be smaller.

What UK conferences usually ask for

There is no single rule. Organisers set the size to fit their display boards, so always read the poster guidelines first. Some real examples:

• Either A0 or A1: The OR Society says posters “should be A1 or A0 in size” and asks for portrait orientation for A0, on boards two metres high by one metre wide (OR Society poster guidelines).
• A1 only, landscape: The British Sociological Association’s annual conference boards take “one poster of A1 size (594mm x 841mm), of landscape orientation” (BSA poster guidelines).
• A1 recommended, A0 maximum: Anglia Ruskin University’s EWIC event recommends A1 portrait and says posters should not exceed A0 (ARU poster guidelines).

If the guidelines give a board size instead of a paper size, choose the largest A-size that fits with a small margin on each side. A0 portrait needs a space at least 84 cm wide and 119 cm high.

When to choose A0

• The conference asks for A0, or allows “up to A0” and the board is large.
• Your poster has several graphs, microscopy images or tables that need to be read from a metre or two away.
• You are presenting in a main poster hall where people walk past quickly and a bigger headline helps you stand out.
• You want to reuse the poster afterwards as a display in your department.

When to choose A1

• The conference asks for A1, or the board is smaller than 85 cm wide.
• It is a poster competition, research day or departmental event with many posters in a small room.
• Your poster is text-light, with one or two key figures and a clear message.
• You are travelling by train or plane and want a shorter poster tube to carry.

Changing between A0 and A1

Because both sizes have the same shape, you can scale a design from A0 to A1 (scale to 71%) or from A1 to A0 (scale to 141%) without distortion. Two things to check:

1. Text size: scaling A0 down to A1 makes 24pt body text about 17pt. Increase the body text before you export if it will be read from more than a metre away.
2. Image resolution: scaling A1 up to A0 makes images softer. Make sure photos and figures are still at least 300 DPI at the final size. Our artwork guide explains how to check this.

Ordering your poster

Order A0 poster printing from £34.99 or A1 poster printing from £29.99, both with free UK delivery in 2–3 working days. Order before 12PM (Monday to Friday) for same-day printing, and choose DPD Next Day (£9.99) or Royal Mail Special Delivery (£12.99, guaranteed by 1PM) if your conference is close. For a full comparison of every size, see our poster size guide.