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‘Is A3 bigger than A4?’: A Printer Paper Size Guide

28 March 2023

Close up of printer

Printing is often overlooked, but sometimes we require specific printing jobs that go beyond a basic A4 one-pager. This means using various paper sizes, leading to questions like ‘Is A3 larger than A4?’

As paper sizes follow a reverse scale, it can be confusing. To clear up any confusion, we will discuss common paper sizes, their appearance, and their applications.

One of the most commonly asked questions: ‘Is A3 bigger than A4?’

The answer?


Paper sizes are confusing as they operate on a reverse scale, with the largest dimensions being the smallest number. To clarify this, we will discuss common paper sizes, their appearance, and applications.

How many different sizes are there?

Paper comes in various sizes and classes. The A-class, which is commonly used, has the correct ratios allowing it to be folded perfectly in half to create the next smaller size.

Printer paper sizes

Paper mm cm inches
A0 841 x 1189 mm 84.1 x 118.9 cm 33.1 x 46.8 inches
A1 594 x 841 mm 59.4 x 84.1 cm 23.4 x 33.1 inches
A2 420 x 594 mm 42 x 59.4 cm 16.5 x 23.4 inches
A3 297 x 420 mm 29.7 x 42 cm 11.7 x 16.5 inches
A4 210 x 297 mm 21 x 29.7 cm 8.3 x 11.7 inches
A5 148.5 x 210 mm 14.85 x 21cm 5.8 x 8.3 inches
A6 105 x 148.5 mm 10.5 x 14.85 cm 4.1 x 5.8 inches
A7 74 x 105 mm 7.4 x 10.5 cm 2.9 x 4.1 inches
A8 52 x 74 mm 5.2 x 7.4 cm 2.0 x 2.9 inches
A9 37 x 52 mm 3.7 x 5.2 cm 1.5 x 2.0 inches
A10 26 x 37 mm 2.6 x 3.7 cm 1.0 x 1.5 inches


A0 is the largest paper size at 841 x 1189 mm, equivalent to 16 pieces of A4 paper stacked vertically. It is used for creating large signs and posters.


A1 paper size is 594 x 841 mm, smaller than A0, but still suitable for making signs, window displays, and posters.


A2 paper size measures 420 x 594 mm and is suitable for creating notices, posters, art prints, and window displays. It is slightly larger than a British broadsheet newspaper.


A3 paper size is 297 x 420 mm, similar in size to a tabloid newspaper but with different proportions. It is commonly used for posters, plans, charts, and presentations in work or school settings. Although not commonly used at home, many business smart inkjet printers can print A3, some even from an A4 machine.


A4 paper size is the most common and recognized paper at 210 x 297 mm. It is widely used in the UK for printing everyday documents such as Word documents and stationery letterheads. It is the standard home printing format, and all laser and inkjet printers, as well as some mobile printers, should be capable of printing A4.


A5 paper size measures 148.5 x 210 mm and is commonly used for flyers, invitations, booklets, planners, and diaries due to its handy and portable size. Many standard home printers offer A5 printing, as it is half the size of A4 and allows two A5 prints to be printed on one sheet of A4. Some mobile printers also offer A5 printing.


A6 paper size measures 105 x 148.5 mm and is commonly used for flyers, postcards, leaflets, and save the dates. It may be too small for long blocks of text, but some mobile printers offer the capability to print this size.

Scrapbook paper sizes

These are designed to fit the most popular sizes of scrapbook albums.



6 x 6 in 15.2 x 15.2 cm
8 x 8 in 20.3 x 20.3 cm
12 x 12 in 30.5 x 30.5 cm



What does GSM mean?

GSM (grams per square metre or g/m²) measures the thickness or density of paper by calculating the weight of a sheet of paper that is one square metre in size. Paper with a higher GSM will be thicker and more resistant to creasing or tearing.

GSM thickness

80-100 gsm Thin paper
100-120 gsm Medium weight paper
120-160 gsm Thick paper
160-200 gsm Thin card
200-300 gsm Medium weight card
300+ gsm Thick card

Stationery GSM thickness

Best for card making 180gsm
Best for die cutting 200-220gsm
Best for origami 120gsm
Best for brush lettering Any weight of smooth paper or card