Card Sizes

When choosing paper and card supplies for your DIY cards or event invitations, we know it can be difficult to decide what size of paper to get. With so many size options available, we thought we’d make things easier for you with this paper, card and envelope size guide.

The Paperbox is your one-stop online shop for all your card and paper supplies, from our popular A4 card and paper sheets to card blanks and envelopes. All of our products are sourced from our partner paper mills and merchants in the UK and Europe.

Card Sheets and Paper Sizes Explained

The Paperbox offers premium paper and card sheets in the following sizes.

Paper and Card Sheets Sizes at The Paperbox
	Millimetres	Centimetres	Inches
A4	210 x 297 mm	21 x 29.7 cm	8.3” x 11.7”
A5	148 x 210 mm	14.8 x 21 cm	5.8” x 8.3”
A6	105 x 148 mm	10.5 x 14.8 cm	4.1” x 5.8”
A7	74 x 105 mm	7.4 x 10.5 cm	2.9” x 4.1”
5 x 7	127 x 17.78 mm	12.7 x 17.78 cm	5” x 7”

Our paper and card sizes are organised using the ISO 216 standard, which includes the common A4 size used in most countries except Canada, the United States, Mexico, Colombia and the Dominican Republic.

The “A” system is organised through an ascending sequential order. In other words, the lower the number after the “A”, the larger the paper size. For example, A4 is double the size of A5, A5 is double the size of A6 and so on.

Paper and Card Sizes in Relation to Each Other
A4	The size of paper you would typically use in your printer and receive and send letters in.
A5	half the size of A4.
A6	half the size of A5 and one quarter the size of an A4 sheet.
A7	half the size of A6, one quarter the size  of A5 and 1/8 of an A4 sheet.

Below are two diagrams showing our paper and card sizes, giving you a visual representation of how A5, A6 and A7 paper sizes fit inside an A4 sheet of paper.

A card blank is a sheet of card that has already been cut and creased for folding, and may be supplied with an envelope or purchased separately. The stated card size usually refers to the finished folded card rather than the unfolded sheet, which is important when selecting envelopes and planning artwork.

We also have a collection of 5” x 7” paper and cardstock in different colours and finishes, perfect for elegant crafting and card making.

How Big Are A4, A5, A6 and A7?

A4 is the most common size for letters, forms, office documents, craft templates and home printing. A5 is widely used for leaflets, flyers, notebooks, invitations and small booklets. A6 is suitable for postcards, small invitations, recipe cards, inserts and compact greeting cards.

A3 is useful for posters, certificates, menus, artwork and larger craft projects. DL is a long, narrow format measuring approximately 99 x 210 mm for paper, although DL envelopes commonly measure 110 x 220 mm. DL leaflets are often made by folding an A4 sheet into thirds.

The most suitable size depends on the available printer, the amount of content and how the finished item will be stored or posted. Choose the finished size first, then select an unfolded sheet or card blank that can be folded to achieve it.

Which paper size is best for printing?

A4 is usually the most convenient size for home and office printing because most UK printers are designed for it. It provides enough space for letters, worksheets, menus, flyers and artwork without requiring specialist equipment.

A5 and A6 designs can often be printed on A4 paper and trimmed or folded afterwards. This can be more economical when producing several smaller items, but you must allow for printer margins, trimming and fold positions.

For professional printing, choose the final size based on the purpose of the item. Check the printer’s maximum sheet size, printable area, paper-feed capability and recommended card weight before buying materials.

Paper sizes for different projects

Choosing the correct size and paper weight at the planning stage can reduce trimming, paper waste and postage problems. A5 is a versatile size for wedding invitations, party invitations, event details and formal announcements.

A6 is suitable for simple invitations containing limited information and is a common greeting card size for everyday occasions. A 5 x 7 inch format offers a slightly wider design area for wedding stationery and photographic invitations.

A4 is convenient for home printing, cutting, templates, card making and small scrapbook layouts. A5 and A6 pieces are useful for journalling, mini albums, tags, inserts and layered embellishments.

Card Blanks

The Paperbox offers pre-creased card blanks in the following sizes.

Card Blank Sizes at The Paperbox
	Millimetres	Centimetres	Inches
A5	148 x 210 mm	14.8 x 21 cm	5.8” x 8.3”
A6	105 x 148 mm	10.5 x 14.8 cm	4.1” x 5.8”
DL	100 x 210 mm	10 x 21 cm	4” x 8.2”
Small Square	122 x 122 mm	12.2 x 12.2 cm	4.8” x 4.8”
Large Square	147 x 147 mm	14.7 x 14.7 mm	5.7” x 5.7”
5 x 7	127 x 177 mm	12.7 x 17 cm	5” x 7”

Our card blanks are described by their measurements once folded — that is, the front-facing side of the card. For example, an A5 card blank is an A4 sheet — which, when folded in half, becomes a card with an A5-sized front.

We also offer card blanks in small square and large square sizes. These are perfect as speciality greeting cards for birthdays, thank you cards and corporate celebration cards.

Below is an image that breaks down the card blanks we provide and their size in relation to an A4 size sheet of paper.

Be sure to check out our collection of pre-creased and flat packed 5” x 7” card blanks, available in a wide variety of colours and elegant finishes.

Envelope Size Guide

Our premium envelopes are available in C5, C6, C7, large square, small square and 5” x 7” sizes. Here is our envelope sizing guide.

Envelope Sizes at The Paperbox
	Millimetres	Centimetres	Inches
C5	162 x 229 mm	16.2 x 22.9 cm	6.38” x 9.02”
C6	105 X 148 mm	10.5 x 14.8 cm	4.49” x 6.38”
C7	83 x 112 mm	8.3 x 11.2 cm	3.30” x 4.40”
DL	110 x 220 mm	11 x 22 cm	8.67” x 4.3”
Small Square	130 x 130 mm	13 x 13 cm	5.11” x 5.11”
Large Square	155 x 155 mm	15.5 x 15.5 mm	6.1” x 6.1”
5 x 7	133 x 184 mm	13.3 x 18.4 cm	5.2” x 7.2”

 

Unlike paper sheets and card blanks, UK envelope sizes are categorised using a “C” and an accompanying number — the latter corresponds to a matching paper or card blank size. For example, a C5 envelope will fit an A5 card blank or an unfolded A5 sheet of paper.

Envelope Sizes in Relation to Card Blank Sizes and Paper Sheet Sizes
C5	C5 envelopes fit an A5 card blank or A4 paper folded in half.
C6	C6 envelopes fit an A6 card blank or A5 paper folded in half.
C7	C7 envelopes fit an A7 card blank or A6 paper folded in half.
DL	Traditional DL envelopes fit an A4 card blank folded twice or a folded A5 card blank.

 

We also carry a collection of 5” x 7” envelopes for your event invites, wedding invitations and greeting cards.

Note that each envelope’s measurements are slightly larger than the actual size of the card blank or sheet, providing enough room for anything else that may need to be added. If they were the same size as the card, the card would never fit inside. This is particularly important for 5” x 7” envelopes, which, despite their name, are actually slightly larger (measuring 5.2” x 7.2”) than 5” x 7” inserts.

Here’s a visual breakdown of the envelopes and their matching card blanks available on The Paperbox, with their sizes illustrated in relation to an A4 size sheet of paper.

If you need a quick visual reference guide while shopping for our card and paper supplies, go ahead and save the image below.

Quick Reminders before Choosing Paper Sizes

Although the “A” paper size system is used around the world, it may not be familiar to consumers in North America as well as parts of South America and Asia that use inch-based systems. Examples of loose paper sizes under this system include Letter, Legal and Tabloid.

Furthermore, the “A” system should not be confused with the SRA paper size system. SRA, which stands for “supplementary raw format A,” is typically used for printing and is slightly larger than standard “A” series sizes.

Order Now to Get Free UK Shipping on Select Orders

Order your paper supplies, card blanks and envelopes from The Paperbox to get FREE standard UK shipping on select orders. We also offer express delivery and next-day delivery for urgent orders. The Paperbox also ships to the Republic of Ireland and select parts of Europe. Visit our Delivery and Returns page for more details.

Whatever the occasion, make it personal and special with premium-quality paper and card supplies from The Paperbox.