Envelope calculator
Type your card’s size: you get the paper, the marks and how to fold it.
How to make it
My card is an odd size. Does that work?
Yes, that is what this is for. A card cut with a die, or folded to your own size, gets an envelope of its own: type its width and height and you get the paper and where to mark it. Fractions work too: 4 3/8, or 4⅜.
Which paper works best?
Paper of about 100 to 150 g/m² folds cleanly and holds its shape.
- 120 g printer paper and most design paper work well.
- Cardstock above about 180 g/m² gets bulky at the seams.
- On thin paper, score gently, or it tears.
My envelope came out too small. What went wrong?
Check these:
- Is the paper exactly square?
- Is the first mark right? Everything after it follows from it.
- Does your card have layers or 3D bits? Then pick Layers or 3D, which gives it more room.
Under ‘Envelope inside’ you see the real size.
Can I mail it?
Yes, as long as it’s big enough. The calculator warns you when it isn’t.
- In the US a letter has to be at least 3½ × 5″ (USPS (opens in a new tab)).
- A nearly square one, or one more than 2½ times as long as it is high, costs extra postage there.
- In the Netherlands it has to be at least 14 × 9 cm (PostNL (opens in a new tab)).
The paper is bigger than my board. Now what?
Score as far as the groove goes, then finish the line with a ruler and a scoring tool. A large envelope still works, it only takes a little longer.
Can I make one without a board?
Yes: pick Pencil and ruler. You draw a pencil line 1 cm in from the edges, mark the points on it and draw the score lines by hand. The steps say how.
How does it work out the sizes?
An envelope starts as a square. Four diagonal folds turn it into a rectangle: that is the inside. So the paper is the card’s width plus its height, divided by 1.41, plus a margin: where the folds cross, a little in from the edge, and some room for the card. The chart printed on a popular board, all 66 sizes, follows this within 1/8″.