Like paper, there are standard sizes of card blanks available to buy. Each is given a code depending on the size of the card.


What size is A6 card? It is 105 x 148mm. It's understandable if you're confused – the names for card codes reference a card that is folded in half. Rather than the size of an unfolded piece of card, the sizes and measurements reflect the size of the folded card or the front face. For example, an A5 card when unfolded will be A4 paper size. Folding it in half pushes it up a number, so an A4 sheet of card will make an A5 card when folded in half. So what size is A7? Well, A7 is half of A6. What size is A6? Yup, you guessed it, A6 is half of A5, which is half of A4.

As with paper sizes, the smaller the number is, the bigger the card blank will be. The common A paper sizes in the UK are based on the ISO 216 (International Standard) paper sizes. All A paper sizes in the ISO 216 system have the height-to-width ratio as the square root of two to one. Don't worry too much about this – it just means that all A named papers will have the same aspect ratio. Americans use US letter as their basic paper size rather than the ISO 216 A system. So the two naming systems will not match up.

Whether you are going to buy card blanks to decorate yourself or make your own cards, it is good to know the common sizes of card available in the UK. Card sizes are different in the US, so it's important not to get, for example, size A6 US mixed up with size A6 UK as they are different sizes. This article is specifically about UK paper and card sizes.

Crafting to the standard sizes will mean it is much easier to buy envelopes for your cards and can make it cheaper to post your cards in some countries.Iif you're following a tutorial, they might list A5 card, A6 card etc. So it's useful to know now and save time wondering what size is A6. It is handy to know your card weights when buying standard cards too. High quality card will be thicker and more sturdy than thinner, cheap card. Any paper above 150gsm (grams per square meter) can be considered high quality and suitable for card making.

More like this

If you would like to learn how to make cards, why not browse through some of our projects? There are lots to choose from, and you can even download some free patterned paper to get started!

a5 size

What size is A4 card?

A4 card size is a sheet of A3 card folded in half

  • 210 x 297 mm
  • 8.3 x 11.69in

What size is A5 card?

A5 card size is a sheet of A4 card folded in half

  • 148 x 210mm
  • 5.8 x 8.3in

What size is A6 card?

A6 card size is a sheet of A5 card folded in half

  • 105 x 148mm
  • 4.1 x 5.8in

What size is A7 card?

A7 card size is a sheet of A6 card folded in half

  • 74 x 105mm
  • 2.9 x 4.1in

What size is DL card?

DL cards are longer and thinner than other card sizes and are a third of a sheet of A4.

  • 210 x 99mm
  • 8.3 x 3.7 in
Card sizes of A4, A5, A6 and A7 card

Envelope sizes

Envelope sizes use the C label format of the ISO 216 system. C envelopes are designed to work with card blanks with the same number. A C5 envelope is designed to fit an A5 card, a C6 envelope will fit an A6 card and a C7 envelope will fit an A7 card. The envelopes will be slightly larger than the card so that the card can fit inside the envelope. A DL sized card will fit inside a DL envelope.

What size is a C4 envelope?

A C4 envelope is slightly larger than an a A4 card, so that the card will fit inside the envelope

  • 229 x 324mm
  • 9 x 12.75in

What size is a C5 envelope

A C5 envelope is slightly larger than an a A5 card, so that the card will fit inside the envelope

  • 162 x 229mm
  • 6.3 x 9in

What size is a C6 envelope?

A C6 envelope is slightly larger than an a A6 card, so that the card will fit inside the envelope

  • 114 x162mm
  • 4.5 x 6.3in

What size is a C7 envelope?

A C6 envelope is slightly larger than an a A6 card, so that the card will fit inside the envelope

  • 81 x 114mm
  • 3.2 x 4.5in

What size is a DL envelope?

A DL envelope is slightly larger than an a DL card, so that the card will fit inside the envelope

  • 110 x 220mm
  • 4.3 x 8.6in
Creative vector illustration of white blank paper envelopes template set isolated on transparent background. International standard sizes

The above illustration show standard envelope sizes and how they relate to the different ways a sheet of A4 card can be folded to fit the envelope. The illustration is by happy_vector for iStock.

standard card sizes envelope

It's easy to make your own envelopes using our free templates. You can make them super decorative or simply crated – the choice is yours. Find the free envelope template

Want to make more of envelopes in your craft project? Take a look at our glorious free stationery papers for more inspiration and free printable artwork. Try our How to make an envelope tutorial to show you the process step by step.


About our expert

a picture of hannah bellis wearing a red dress

Hannah Bellis

Hannah Bellis was the editor of Papercraft inspirations magazine for four years. She has extensive knowledge and experiences of the papercraft market and different card making techniques. She has taught different card making technique workshop at craft shows on behalf of Papercraft inspirations. She has demonstrated hundreds of different card making techniques in video tutorials for the Papercraft TV Youtube channel.


Hannah BellisKnitting Editor, Gathered

Hannah has worked on Gathered for 3 years, since our launch in 2019. At school Hannah learned to knit collaborating on dorcas blankets – now she edits our knitting section. She inherited her love of stitching and embroidery from her talented grandmother, and her passion for thread led her to be Editor of The World of Cross Stitching for six years. Card making is a more recent passion, developing from her position as editor of Cross Stitch Card Shop. She loves using kinetic techniques to make cards that move – she was editor of Papercraft inspirations magazine for over four years, creating loads of card making video tutorials at

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