Whether you are planning a stack of handmade cards, a chunky junk journal or a heritage scrapbook album, two numbers decide a surprising amount about how your project turns out: the size of the paper and its weight. This Craftywafty paper size guide explains both in plain, crafter-friendly language, so you can buy, cut and print with confidence.

Why Paper Size Matters in Crafting

Craft supplies come from all over the world, so metric sizes (A4, A5, A6), imperial sizes (12x12 in, 8x8 in) and American office sizes (Letter, Legal) all end up in the same basket. Knowing how they relate helps you match cards to envelopes, get the most from every sheet, and print at the right size.

The ISO A Series: A4 Size in mm and Friends

The A series is the standard in the UK and most of the world. It is defined by the international standard ISO 216, and it has a clever trick: every size is made by folding the one before it in half across its longer side. So each step halves the previous size, and every sheet keeps the same proportions (a ratio of roughly 1 : 1.414).

The starting point is A0, which has an area of one square metre. Everything else follows from that.

Size	Width x Height (mm)	Width x Height (inches, approx.)	Crafty uses
A0	841 x 1189	33.1 x 46.8	Large posters and plans
A1	594 x 841	23.4 x 33.1	Posters, flip charts
A2	420 x 594	16.5 x 23.4	Large art boards, display work
A3	297 x 420	11.7 x 16.5	Mixed media sheets, large artwork
A4	210 x 297	8.3 x 11.7	Home printing, card stock, journal pages
A5	148 x 210	5.8 x 8.3	Card bases, notebooks, journal inserts
A6	105 x 148	4.1 x 5.8	Small cards, postcards, tags
A7	74 x 105	2.9 x 4.1	Mini cards, gift tags, journal ephemera
A8	52 x 74	2.0 x 2.9	Tiny tags, trading-card-sized pieces
A9	37 x 52	1.5 x 2.0	Miniature crafts
A10	26 x 37	1.0 x 1.5	Very small embellishments

If you only remember one figure, make it this one: A4 is 210 x 297 mm. For most crafters, A4 and A5 do the bulk of the work.

Cutting One Sheet into Smaller Sizes

Because each step halves the last, the sums are easy:

·      One A4 sheet gives 2 x A5

·      One A4 sheet gives 4 x A6

·      One A4 sheet gives 8 x A7

·      One A3 sheet gives 2 x A4, or 4 x A5

A folded A5 card is simply an A4 sheet folded in half, which is why A5 is such a popular card size.

B and C Series: The Supporting Cast

The B series sits between the A sizes and is mostly used for books and some journals. B5 is 176 x 250 mm and B6 is 125 x 176 mm, so check before buying inserts.

The C series is the one that matters most to cardmakers, because it is the standard for envelopes. A C-size envelope is designed to hold the matching A-size sheet. An A5 sheet fits a C5 envelope with a little room to spare, and so on.

Envelope	Size (mm)	Holds
C7	81 x 114	A7 card
C6	114 x 162	A6 card, or an A5 card folded again
C5	162 x 229	A5 card, or an unfolded A5 sheet
C4	229 x 324	A4 sheet, flat
DL	110 x 220	A4 folded in three, or a DL card

DL is not strictly part of the C series, but it is so common it earns its place here.

Scrapbooking and Craft Paper Sizes

Many scrapbooking and papercraft ranges follow imperial measurements, which is why you will see inches on paper pads even in the UK. 12x12 scrapbook paper size is the classic: a square sheet measuring 12 x 12 inches, which is 304.8 x 304.8 mm. It is based on the US and imperial tradition and has become the standard in the scrapbooking world, largely because it suits layouts and album pages so well.

Size (inches)	Size (mm, approx.)	Popular for
12 x 12	305 x 305	Scrapbook layouts, album pages, big paper pads
8 x 8	203 x 203	Square cards, mini albums, pad papers
6 x 6	152 x 152	Small square cards, layers, mini projects
6 x 8	152 x 203	Pad papers, card layers, journal pages
5 x 7	127 x 178	Classic card size, photo mats
4 x 6	102 x 152	Photos, journaling cards, small cards
4 x 4	102 x 102	Mini squares, embellishments

(Millimetre figures are rounded to the nearest whole number.)

Cutting Down 12x12 Paper

A 12x12 sheet is wonderfully easy to divide:

·      4 x 6x6 squares (cut in half each way)

·      9 x 4x4 squares (cut into thirds each way)

·      2 x 6x12 strips, which are ideal for borders and journal spines

·      6 x 4x6 pieces, perfect for journaling cards and photo mats

A 12x12 sheet is larger than A4 in both directions, so it will not fit a standard A4 printer. Many crafters print on A4 and trim, or use a wide-format printer.

US Paper Sizes vs A4

If you buy printables or digital downloads from US designers, you may find they are set up for Letter size. They are close to A4, but not the same.

Name	Size (inches)	Size (mm)
A4	8.27 x 11.69	210 x 297
US Letter	8.5 x 11	215.9 x 279.4
US Legal	8.5 x 14	215.9 x 355.6
US Tabloid	11 x 17	279.4 x 431.8

The key differences: Letter is about 6 mm wider than A4 but roughly 18 mm shorter. Printing a Letter design onto A4 usually works if you choose “fit to page”, but you may see slightly larger margins at the sides. If you are printing journal pages or card toppers, a quick test print saves paper and ink.

UK Card Blank and Envelope Pairings

Card blanks are the folded cards you decorate. Sizes vary a little between brands, so always measure or check the product description, but these are the common pairings.

Card blank	Folded size (approx.)	Usual envelope
A6	105 x 148 mm	C6 (114 x 162 mm)
A5	148 x 210 mm	C5 (162 x 229 mm)
5 x 7 in	127 x 178 mm	5 x 7 in envelope, usually around 133 x 184 mm
6 x 6 in	152 x 152 mm	6 x 6 in square envelope, usually around 155 x 155 mm
8 x 8 in	203 x 203 mm	8 x 8 in square envelope, usually a few mm larger
DL	99 x 210 mm	DL (110 x 220 mm)

A few friendly tips:

·      Square cards can be charged differently for postage, so check Royal Mail’s current size rules before sending a batch.

·      Thick embellishments may call for a slightly roomier envelope.

·      Envelope sizes vary a little between makers, so try a small pack first.

What Is GSM?

Now for the other half of the story. What is GSM? It stands for grams per square metre, and it tells you how heavy a sheet of paper is for a given area. A 1-metre-by-1-metre sheet of 300 GSM card would weigh 300 grams.

An A4 sheet is one sixteenth of a square metre, so 80 GSM A4 weighs about 5 g and 300 GSM A4 about 19 g. Handy for postage sums.

GSM is a measure of weight, not thickness. Two papers with the same GSM can feel different, because the fibres, coating and finish all affect how bulky the sheet is. Generally, though, higher GSM means a thicker, stiffer, sturdier sheet.

Why GSM Matters for Crafting

·      Stiffness and durability: card bases need to stand up, and albums get handled a lot.

·      Printer compatibility: most home printers handle up to about 200-250 GSM, but always check your printer’s manual.

·      Folding and scoring: thicker card can crack along a fold unless it is scored first.

·      Wet media: watercolour, ink and gel medium need heavier paper to avoid buckling.

·      Die cutting: intricate dies usually cut cleaner on thinner card, while thicker card suits bold shapes and may need extra passes through your machine.

·      Postage: paper weight adds up, particularly with layered handmade cards.

Card Weight Guide: GSM Ranges and Uses

The ranges below are a general card weight guide. Different brands label things differently, so treat these as helpful signposts rather than strict rules.

GSM range	Typical type	Great for
70-100	Office and printer paper	Everyday printing, templates, practice sheets
100-120	Lightweight patterned or scrapbook paper	Journal backgrounds, collage, decoupage
120-160	Heavier paper, light card	Layering behind panels, envelope liners, paper crafts
170-220	Light cardstock	Card toppers, mats, liners, scrapbook layers
220-300	Standard cardstock	Card bases, tags, die-cut shapes
300-350	Heavy cardstock	Sturdy card bases, 3D projects, detailed die cuts
350+	Thick card and boards	Album covers, boxes, chipboard, structural projects
200-300+	Mixed media and watercolour paper	Inks, paints, gesso, wet techniques

A popular combination is a 300 GSM base with lighter layers on top.

Scoring and Grain Direction

Two small habits make a big difference with heavier card:

·      Score before you fold. A scoring board and bone folder give a neat crease, and the card is much less likely to crack.

·      Check the grain. Paper fibres tend to line up in one direction. Folding along the grain gives a smoother fold, and folding across it can look rougher. If your paper has a visible grain, fold with it where you can.

GSM, lb and US Paper Weights

If you shop from American suppliers, you may see weights in lb instead of GSM. This is where confusion creeps in, because US pounds are based on the weight of a ream at a specific, uncut size, and that size differs between paper types. A “100 lb” cardstock is therefore not the same weight as “100 lb” text paper.

You cannot convert lb to GSM with one single number. Here are some approximate comparisons:

US description	Approximate GSM
20 lb bond	75
24 lb bond	90
65 lb cover	176
80 lb cover	216

These are approximate and depend on paper type, so when a listing gives both, trust the GSM.

Frequently Asked Questions

What is the size of A4 in mm?

A4 is 210 x 297 mm, or about 8.27 x 11.69 inches.

Is 12x12 scrapbook paper the same as A4?

No. A 12x12 inch sheet is 305 x 305 mm, a square, whereas A4 is 210 x 297 mm. They have different shapes and sizes.

How many A6 cards can I cut from one A4 sheet?

Four. Fold or cut A4 in half to make two A5 pieces, then halve again to get four A6 pieces.

What GSM is best for card bases?

Most cardmakers choose between 250 and 350 GSM. Around 300 GSM is a popular choice, as it is sturdy but still easy to fold and run through a die-cutting machine.

Can my home printer handle heavy cardstock?

Many can handle card up to roughly 200-250 GSM, but it varies by model. Check your printer’s manual, try a single sheet first, and use the rear or straight-through paper feed where available.

Final Thoughts

Once you know A4 is 210 x 297 mm, each A-size halves the last, and GSM tells you how sturdy a sheet is, planning gets much easier.

Craft paper is sold by lots of shops just search Google, so shop around there is plenty of choice, you may also find using materials or cuttings available at home or amongst crafters at a club that do swap shops, you can acheive a lot without spending your budget, but if you would like a convenient place to browse papers and cards for your next project, you are welcome to take a look at our card making and scrapbooking paper and card collection.

Happy crafting!

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