What is A3 Paper Size?

Introduction

A3 is the size that usually works for most tasks.  A4 is okay but can feel squished. A2 gives plenty of space but is harder to hold. With A3, you can fit text, pictures, or diagrams without crowding. Folding or resizing it doesn’t change how it looks. It's big enough for details but small enough to handle easily.

You’ll see it in schools, offices, or art spaces. Lay it out, fold it, or put it away; it's simple to use all around.
But how useful is it exactly? We’ll tell you all about that in this article, as well as some of its best use cases and other paper sizes. Keep reading.

Table of Contents

1. What is A3 Paper Size?

A3 is in the A-series. Every sheet keeps the same 1:√2 shape. Cut it along the long side, and you get two A4 sheets. Stack two of them, and you have A2. 

One-quarter of A1, one-eighth of A0, four times bigger than A5- everything works this way so you can get the right measurements to make folding and scaling easy.

The A3 shape helps layouts stay tidy. Text, images, or charts keep their balance. People use A3 for sketches, drafts, or simple layouts. It’s big enough to show detail but still easy to hold. You can write, draw, or fold it without it feeling awkward.

2. A3 Paper Size: Dimensions and Weight

A3 feels easy and open. You can spread your ideas out without feeling cramped. Take a look at the page, and you’ll see everything fits without crowding.

For quick notes or rough sketches, a 90 gsm sheet is easy and light. Once you want the paper to last a bit longer or feel tougher, 160 gsm is a good middle ground. Posters, displays, or anything that should stay firm do better on 220 gsm. You can lay sheets flat, stack them, or roll a few to take with you, and they’ll stay in good shape.

Here’s a demonstration.

A-series Sizes Table of Dimensions

Pixel size changes with dpi. At 72 dpi, A3 is 842 × 1,191 px. At 150 dpi, 1,754 × 2,480 px. At 300 dpi, 3,508 × 4,960 px. At 600 dpi, 7,016 × 9,933 px. This helps check how sharp prints or screens look.

3. Applications of A3 Paper Size

Compared to other options, A3 has a lot of uses with both everyday and professional things.

• Office use: You can put a chart on A3 and still have room to write notes next to it. Even a quick handout looks clear, and nothing feels cramped.

• School projects: Kids or students use A3 for posters or art. It’s big enough to draw, stick things, and add labels without stuff bumping together. You can also show it to others easily.

• Design and photography: A3 gives space to move sketches or photos around. You can see how things fit before finishing, and it’s big enough for detail but not too heavy to hold.

• Shops and restaurants: Menus, small flyers, or signs work on A3. People can read them fast, and they fit on a counter, wall, or window without taking over.

• Home use: Planning boards, calendars, or craft work sit nicely on A3. You can spread things out, leave sheets flat, or roll a few to carry around.

• Creative projects: Posters or leaflets fit well. You can mix text and images, fold them if you need, and move them around without feeling crowded.

4. A3 Paper Size Resolution 

A3 gives you space to spread your work, but you need the right resolution to actually see details. At 300 dpi, a page is about 3508 × 4961 pixels, where text stays sharp and lines stay clear. Charts, labels, and small drawings will become easy on the eyes when reading.

Quick tips:

• For rough drafts or sketches, 150 dpi works fine. It’s faster and makes smaller files. It's good for notes, brainstorming or quick layouts.

• For posters, artwork, or anything with tiny lines or text, 600 dpi works more reliably at keeping everything crisp.

For example, you can scan a school project with charts and drawings. At the right resolution, all lines, colors, and labels stay visible. At low resolution, everything starts to blur.

5. How to Print with A3?

Printing A3 works like this:

Step 1: Look at the Printer

Some printers only take A4. Bigger printers take A3. The paper needs to sit flat in the tray.

Step 2: Pick Paper

Matte cuts glare, works for text. Glossy makes colors bright for photos or flyers. Thick paper stays firm for posters and thin paper works for drafts.

Step 3: Pick Page Layout

Portrait or landscape. Margins and bleed matter if the design goes to the edge.

Step 4: Pick Resolution

300 dpi is good for most prints. Higher dpi helps with tiny lines or detailed work.

Step 5: Print One First

Look at the first print. Then print more. Some printers do batches, some need one sheet at a time.

A3 will give space to spread out work. Folds, trims, and alignment are going to happen naturally if you handle it carefully.

6. How Do I Scan A3-size Documents?

If you have an A3 flatbed scanner, simply place the A3 document flat on the scanning surface.

Steps:

1. Open the scanner lid and place the A3 document on the glass.
   

2. Align it with the corner or measurement markings to ensure correct positioning.
   

3. In the scanning software, select:
   

• Size: A3 (297 × 420 mm)
  

• Resolution: 300 dpi for documents, 600 dpi for images
  

• Color: Color or grayscale as needed
  

4. Click Scan and save the file as PDF or JPG.
   

But some A3 pages are big, and some books are pretty thick. Most regular scanners struggle to handle this size—they can create shadows, glare, or even miss parts of the page. Trying to press a bulky notebook flat is inconvenient, too. If you want clear lines and sharp text, you’ll need high-resolution scanning to capture all the details. That’s why an overhead document scanner is often the better option.

You can start a scan in different ways- by hand, pedal, software, or auto mode- which helps when you’re working through a stack of pages or a thick notebook.

6.1 Our recommendation: CZUR ET Max

The ET Max handles larger sheets and thicker pages with no bumps. It captures 38 MP at 410 dpi. It can flatten curves, remove fingers, and notice page turns automatically. Works on Windows, macOS, and Linux. Pages usually come out clean. Files will save directly to Word, Excel, PDF, or common image formats. It makes scanning bigger documents feel much easier. If you want to boost your scanning efficiency, give the ET Max a try.

Figure2-ET Max

Conclusion

A3 gives you extra room compared to A4 but stays easier to handle than A2. You can spread things out, see details, and still carry or store them. Once you get what A3 size is, you’ll know how to use it for posters, office sheets, or school projects. It works for almost anything that needs a bit more space than standard paper. Learning to work with A3 makes planning, printing, and sharing your work a lot simpler.