• Award Winning Company

  • Super Fast Shipping

  • Free UK Shipping on Orders > £60 *

  • 5 Star Customer Service

  • 100% Secure Shopping

Card and Paper Size Guide

A Guide to Paper and Card Sizes

International Paper Sizes

This card and paper sizes guide will help you determine the paper formats and metric paper sizes you need for your document or project.

So if you’re looking to answer questions such as ‘What is standard A4 size?’ or ‘What size is A6 compared to A4?’ we have all the information you need!

Whether you’re looking for a standard A0 size or want to know what an SRA3 dimension is compared to other A4 paper, our card and paper size guide provides all the information you need to choose the perfect sizing solution for your project or document.

The A Series

Common paper sizes (UK) are usually determined by the A-series standard of ISO 216 also known as ISO 216 standard.

This is recognised internationally and throughout the world, apart from a few countries such as Canada and the USA, where a different paper sizing system is used.

Card or paper sizes in the A series can be folded or cut in two to create the next smallest size.

  • A0 is 1189 mm x 841 mm, which cuts in two to produce A1, which is 841 mm x 594 mm.
  • When A1 is cut in half, you get A2, which is 594 mm x 420 mm.
  • A3 paper is 297 mm x 420 mm and, when folded in two, produces an A4 sheet of paper, which is 210 mm wide.

This can be repeated until you reach the smallest available, also known as B6.

A0 Paper Sizes
The A series is an internationally recognised paper size

The B Series

The B Series of paper and card sizes are based on a different scaling system than the A Series, but still maintain the same aspect ratio of 1:√2. This series begins with B0, which is 1000 mm x 1414 mm. When cut in two, it produces B1, which is 707 mm x 1000 mm.

B6 is the smallest standardized size in the A Series of paper and card sizes. It measures 125 mm x 176 mm, which is approximately 5 inches wide by 7 inches long. The B Series follows a different scale than the A Series, but both are based on an aspect ratio of 1:√2.

When compared to the A Series, B6 is equivalent to A10.

A4 Paper Sizes and A4 Size

One of the most common paper sizes is A4 and A4 in cm is one of the most recognised standard paper sizes in the world. The international standard size of A4 and the dimensions of A4 paper is 21 cm by 29.7 cm (or 8.27 inches x 11.7 inches). An A3 sheet can be easily divided into two sheets of A4 with a single fold or cut.

A4 to A5 and Envelopes

An A4 paper size is the most popular and commonly used format, perfect for documents like letters and reports. Folding A4 along the short edge into two will fit a C5 envelope, and folding along the short edge into three will fit into a DL envelope. The A4 to A5 percentage is 1:2.

Card and Paper Sizes Guide

SRA3 Dimensions

SRA3 measures 320 x 450 mm or 12.6 x 17.7 inches, and it’s slightly larger than A3.

SRA3 paper is a commonly used size for document printing, particularly in publishing and print.

Print bleed ensures that print elements extend to the edge of the paper or card stock. For this to happen, printers require a slight extension to the document’s artwork, known as a bleed. This is so that when the job is trimmed down, there is no white border around the edges. SRA3 papers and card stocks are generally supplied with a 3mm bleed on all four sides, so make sure to include this when designing artwork for an SRA3 project.

So how big is an SRA3 piece of paper? SRA3 is s 320 mm wide and 450 mm long, and when cut in half it produces two slightly larger than A4-sized sheets of paper.

How big is SRA3:

  • SRA3 size in mm 320 x 450mm
  • SRA3 size in cm 32 x 45 cm
  • SRA3 size in inches 12.6″ x 17.7″

A3 Dimensions

So how big is an A3 piece of paper? A3 is 297 mm wide and 420 mm long, and when cut in half it produces two A4 sheets of paper.

Similarly, one sheet of A3 card will yield two A4 pieces of card ie one A3 sheet will fold in half to make an A4 card blank, which would fit into a C4 envelope.

An A3 page size is popular for posters, presentations and wedding table plans.

How big is A3:

  • A3 size in mm 420 x 297mm
  • A3 size in cm 42 x 29.7cm
  • A3 size in inches 11.7″ x 16.5″
A3 to A4 Paper Size
One A3 sheet cut in half creates two A4 sheets of paper

A4 Dimensions and Dimensions for A4 in Inches

A4 card and paper is probably the paper size most people are familiar with. An A4 paper size in cm is 21 x 29.7cm or alternatively, A4 in mm is 210 x 297 mm.

One of the common questions we’re asked is whats bigger A4 or A5? So what is the difference between A4 vs A5 paper? One sheet of A4 will yield two sheets of A5 when cut in half or if folded, one A5 card blank, which will fit into a C5 envelope.

The majority of desktop laser and inkjet printers will accept A4 printer paper.

How big is A4:

  • A4 size in mm 210 x 297mm
  • A4 size in cm 21 x 29.7cm (A4 dimensions in cm)
  • A4 size in inches 8.3″ x 11.7″ (A4 paper size in inches)
A4 to A5 Paper Sizes
One A4 sheet cut in half makes two A5 postcards or folded in half one A5 card blank

A5 Dimensions

So is A5 smaller than A4? the answer is yes, A5 paper is half the size of A4 or A4 is twice the size of A5. A5 is double the previous size of A4.

A5 card blanks are most commonly used for wedding invitations, order of service booklets or flyers. A common misconception is that A5 is bigger than A4, but in the A series of paper sizes, the number decreases as the size increases.

One A5 sheet of card equals two A6 postcards when cut in half or produce one A6 card blank to fit a C6 envelope.

How big is A5, measurements:

  • A5 size in mm 148 x 210mm
  • What size is A5 in cm 14.8 x 21cm (a5 size in cm)
  • A5 size in inches 5.8″ x 8.3″ (A5 in inches)
A5 to A6 Paper Sizes
One A5 sheet cut in half makes two A6 postcards or folded in half one A6 card blank

A6 Dimensions

A6 card is one-quarter of A4 paper and is familiar to many as the size of a postcard or correspondence card.

You can cut four A6 size paper postcards from one A4 piece.

One of the most common sizes of card blanks for card making is A6, as no waste is produced from a sheet of A4 card.

How big is A6 paper:

  • A6 size in mm 105 x 148.5mm
  • A6 size in cm 10.5 x 14.85cm
  • A6 size in inches 4.1″ x 5.8″
A6 to A7 Paper Size
One A5 sheet cut in half makes two A6 postcards or folded in half one A6 card blank

A7 Dimensions

One sheet of A4 card can be cut into eight A7 postcards (ideal for RSVP’s) or 4 creased A7 card blanks.

How big is A7 paper:

  • A7 size in mm 74 x 105mm
  • A7 size in cm 7.4 x 10.5cm
  • A7 size in inches 2.91″ x 4.13″

So there are a variety of paper sizes available to choose from and the one should you use depends on the project.

The international standard paper size for A4 paper is perfect for most home printers, a letter, printing documents, letters, flyers and small posters.

If you need a smaller size consider using A6 or A5. These smaller options are great for card making and are popular greeting card sizes. For posters and display, a larger size like A3 paper may be more suitable.