A measured blank that fits any card size, the scoring that makes it fold clean, and the no-template method
9 min read
An envelope is a rectangle with four flaps. Cut a blank 1 1/2 inches wider and 4 inches taller than the finished envelope, score a border, fold the sides and bottom in, glue them, and fold the top down. For a standard A2 card that means a 5 7/8 by 9 3/4 inch blank, which cuts one per sheet from 8.5 by 11 cardstock.
The rest of this covers where those numbers come from so you can size an envelope for any card, how to score so the folds are sharp instead of cracked, and the square-of-paper method for when you have no template at all.
Start from the card, not the envelope
Every envelope size is derived from the card that goes in it. The clearance rule is the same one used across card making:
An envelope's interior runs about 1/8 inch wider and 1/4 inch taller than the card.
That gap is what lets a decorated card slide in without catching on the corners. Less and a layered card jams. Much more and the card slides around in the post.
So an A2 card at 4.25 by 5.5 inches needs an envelope interior of 4.375 by 5.75 inches. Full card and envelope dimensions for every standard size are in A2 card size and every standard card dimension.
The blank
Once you know the interior, the flat blank is the interior plus the flaps:
Side flaps: 3/4 inch each. Enough surface to glue, narrow enough that they do not shadow through the front on lighter paper.
Bottom flap: 2 1/4 inches. This is the structural one. It carries the glue seam and takes the weight of the card.
Top flap: 1 3/4 inches. The one you seal. Shorter than the bottom on purpose, so the two do not stack into a ridge.
All measurements in inches. The last column is what you can cut it from.
Card
Card size
Envelope interior
Flat blank
Cuts from
A1
3.5 x 4.875
3.625 x 5.125
5.125 x 9.125
8.5 x 11, one per sheet
A2
4.25 x 5.5
4.375 x 5.75
5.875 x 9.75
8.5 x 11, one per sheet
A6
4.5 x 6.25
4.625 x 6.5
6.125 x 10.5
8.5 x 11, one per sheet
A7
5 x 7
5.125 x 7.25
6.625 x 11.25
12 x 12 only
Square
5.25 x 5.25
5.375 x 5.5
6.875 x 9.5
8.5 x 11, one per sheet
Slimline
3.5 x 8.5
3.625 x 8.75
5.125 x 12.75
12 x 12, with shorter flaps
Two rows are worth reading twice.
A7 does not fit on letter cardstock. At 11.25 inches tall the blank is a quarter inch too long for an 8.5 by 11 sheet, which is why hand-made A7 invitation envelopes are almost always cut from 12 by 12 scrapbook paper. There is no trimming your way around it without shortening the bottom flap below what will hold a glue seam.
Slimline needs shorter flaps even on 12 by 12. At 12.75 inches the standard flap set overshoots. Drop the bottom flap to 1 3/4 and the top to 1 1/2 and the blank lands at exactly 12 inches. That is tight to the sheet edge, so cut it first while the paper is square.
Where to score
Score lines are measured from the edges of the blank, not from the middle. For the A2 blank at 5 7/8 by 9 3/4:
Vertical scores at 3/4 inch from the left edge and 3/4 inch from the right edge. These fold the side flaps in.
Horizontal score at 2 1/4 inches from the bottom edge. This folds the bottom flap up.
Horizontal score at 1 3/4 inches from the top edge. This is the seal flap.
The two vertical scores run the full height of the blank, and the side flaps get trimmed at an angle where they meet the bottom flap so the corners do not bunch. A cut file does that angle for you; by hand, a 45 degree snip at each inside corner is close enough.
Scoring so it folds clean
The difference between a crisp envelope and a cracked one is almost entirely in the scoring.
Score on the outside, fold toward the score. A score crushes fibres on the side the tool touches, and the paper wants to fold away from the crush. Scoring on the wrong face is the usual reason a fold looks torn.
Match the tool to the weight. A stylus and ruler is fine to about 80 lb cover. Above that a scoring board or your machine's scoring stylus gives a deeper channel and a cleaner break. Bone folders are for sharpening a fold after it is made, not for making the score.
Fold within a few minutes of scoring. Cardstock relaxes. A sheet scored and left overnight folds noticeably less sharply than one folded straight away.
Heavier is not better here. Card bases want 80 lb cover or more. Envelopes want less. Text-weight paper around 24 to 32 lb bond, or a light 65 lb cover at most, folds flat and seals without a bulge. Anything heavier makes an envelope that will not lie flat in the post and may attract a non-machinable surcharge on thickness alone. More on choosing weights in how to cut cardstock with a Cricut.
The no-template method: one square of paper
If you have no template and no machine, an envelope folds out of a single square.
Set the square as a diamond, corners at top, bottom, left and right. Put the card in the middle, sitting square, not rotated. Fold the left and right corners in over the card so they overlap slightly at the centre. Fold the bottom corner up over both. Glue those three. Fold the top corner down to seal.
Sizing rule: make the square about one and a half times the card's longer dimension. For an A2 card that is roughly a 8 1/4 inch square. The rule deliberately errs generous, because how big the square needs to be depends on how much flap overlap you want, and a slightly oversized diamond just gives deeper flaps while an undersized one leaves the card showing at the sides. Cut one from scrap paper and check it against your card before cutting the good stuff.
This method wastes considerably more paper than a rectangular blank and leaves diagonal seams on the back, which some people like and some do not. Its advantage is that it needs no measuring beyond the square.
Lining an envelope
A liner is a rectangle of patterned paper glued inside, visible when the flap opens.
Cut the liner 1/8 inch narrower than the envelope interior on each side, and short enough that it stops about 1/4 inch below the fold line of the seal flap. If the liner reaches the fold it stiffens the flap and the envelope will not close flat.
Glue the liner in before assembling the envelope, while the blank is still flat. Doing it afterwards means working inside a finished tube and it is much harder to get square.
Making a batch
Cut every blank in one pass before scoring any of them, and score every blank before folding any. Batching by operation rather than by envelope is meaningfully faster and, more usefully, it keeps the scores consistent, because you are not resetting the board between each one.
For anything past about ten envelopes, a scored cut file is worth it. The angles at the inside corners are the part that is tedious by hand and instant by machine. Browse the free SVG collection or the free cut files for Cricut page. Every download includes SVG, PNG, DXF and JPG, so you can scale a blank to a card size that is not on the table above without losing edge quality.
Frequently asked questions
How do I make an envelope from paper? Cut a blank 1 1/2 inches wider and 4 inches taller than the envelope interior you need, score 3/4 inch in from each side, 2 1/4 inches up from the bottom and 1 3/4 inches down from the top, fold the sides and bottom in and glue them, then fold the top down to seal. For an A2 card the blank is 5 7/8 by 9 3/4 inches.
What size paper do I need to make an A2 envelope? A 5 7/8 by 9 3/4 inch blank, which cuts one per sheet from standard 8.5 by 11 cardstock. That produces an envelope with a 4.375 by 5.75 inch interior, the correct fit for a 4.25 by 5.5 inch A2 card.
Can I make an envelope without a template? Yes. Fold one from a single square of paper set as a diamond: card in the centre, left and right corners folded in, bottom corner up and glued, top corner down to seal. Make the square about one and a half times the card's longer dimension and test it on scrap first, since the right size depends on how much flap overlap you want.
What weight paper should I use for an envelope? Lighter than the card. Text weight around 24 to 32 lb bond, or a light 65 lb cover at most. Heavy cardstock makes an envelope that will not lie flat and adds thickness that can push it over the letter-rate limit.
How do I score cardstock without a scoring board? Run a stylus or an empty ballpoint along a metal ruler, on the outside face of the fold, using firm even pressure in one pass rather than several. This works reliably up to about 80 lb cover. Above that the channel is too shallow and the fold will crack.
Why does my envelope fold crack along the score? Almost always because it was scored on the wrong face. Paper folds away from the crushed fibres, so score the outside and fold toward the score. Heavy cardstock and scores left to sit overnight before folding both make it worse.
Will a homemade envelope go through the mail? Yes, if it is rectangular, under a quarter inch thick and sealed properly. Square envelopes attract a USPS non-machinable surcharge regardless of who made them, and a hand-made envelope in heavy cardstock can hit the thickness limit on its own.
