How to Fold Paper Into an Envelope

This classic origami-style fold turns a standard A4 or letter-size sheet into a self-sealing envelope. It’s perfect for notes, invitations, or small documents when you don’t have a store-bought envelope on hand. All you need is a single rectangular piece of paper—printer paper, wrapping paper, or even a page torn from a notebook works fine.

What You’ll Need

One rectangular sheet of paper (A4, letter-size, or any rectangle with a ratio of about 1:1.5 to 1:2)
A flat surface to fold on
Optional: a bone folder or the edge of a ruler to make crisp creases

Step-by-Step

Start with the paper portrait-style. Place the rectangle on your work surface with the shorter edges at the top and bottom. If your paper has a printed side or a side you want on the outside of the envelope, face that side down.
Fold the bottom edge up to about one-third of the way. Bring the bottom edge upward so it covers roughly the lower third of the paper. The exact distance isn’t critical—just make sure the fold is straight and crease it firmly. This bottom section will become the back of your envelope.
Fold the top edge down to meet the bottom fold. Bring the top edge down so it overlaps the bottom fold by about 1–2 cm (or ½ inch). This creates the front flap of the envelope. Crease well.
Fold the left and right corners of the top flap inward. Take the top-left corner and fold it diagonally toward the center, so its edge aligns with the vertical center of the paper. Do the same with the top-right corner. These folds form the triangular side flaps that will hold the envelope together.
Fold the bottom corners of the top flap inward as well. Now fold the bottom-left and bottom-right corners of the same flap diagonally inward, so they meet the center. This creates a pointed shape at the bottom of the flap—this will be the envelope’s pocket.
Tuck the bottom section into the pocket. Lift the entire top flap (the one you’ve been folding) and slide the bottom folded section (from step 2) up and into the pocket created by the side folds. The bottom edge should fit snugly under the triangular flaps.
Fold the top flap down and tuck it in. Bring the top flap down over the front of the envelope. The pointed tip should slide into the opening at the bottom. Press down to secure it. Your envelope is complete.

Common Mistakes

Uneven folds: If your folds aren’t straight, the envelope will look lopsided. Use a ruler to measure or simply take your time to align edges before creasing.
Too much paper in the pocket: If the bottom section is too long, it won’t tuck easily. Adjust the first fold so the bottom section is slightly shorter than the top flap.
Creasing too lightly: Light creases make the paper spring back. Press firmly along each fold, or use a bone folder.
Folding the wrong side: If you want the printed side to be the outside, make sure it’s facing down at the start. If you want it inside, face it up.

Tips

Use a sheet that’s not too thick—standard printer paper (80–100 gsm) is ideal. Cardstock may be too stiff to tuck neatly.
For a more secure closure, add a small sticker or a dot of glue to the tip of the top flap before tucking it in.
If you’re mailing the envelope, write the address on the front before folding, or leave a blank space on the outside.
Practice with scrap paper first to get the proportions right.

Troubleshooting

The flap won’t stay tucked: The pocket might be too tight. Open the envelope, gently stretch the folds, and re-tuck with less force. You can also fold the top flap’s tip slightly upward to create a smaller tab.
The envelope is too small for your contents: Use a larger sheet of paper. The final envelope size is roughly one-third of the original sheet’s height and about two-thirds of its width.
The paper tears at the corners: This happens if you crease too hard or use thin paper. Be gentler, and consider using a thicker sheet.
The sides gap open: Make sure the side flaps overlap enough—if they don’t meet in the center, the pocket won’t hold. Fold them slightly past the center if needed.

Frequently Asked Questions

Can I use square paper?

Yes, but the envelope will be smaller and more square-shaped. The same folding method works, but the proportions change—just make sure the bottom fold is about one-third of the height.

Will this envelope survive mailing?

It’s fine for hand delivery or as a decorative note, but for postal mail, use a standard envelope or add clear tape over the seams. The tuck can come undone in sorting machines.

How do I make the envelope bigger?

Start with a larger sheet of paper. The final envelope is about one-third the height of the original sheet, so a legal-size sheet (8.5 x 14 inches) gives a roomier envelope.

Can I decorate the envelope?

Absolutely. Draw on the paper before folding, or add washi tape, stickers, or a wax seal after folding. Just avoid making the paper too thick to fold.

What if my paper is too thick to crease?

Use a bone folder or the back of a spoon to press the creases. If it still resists, switch to thinner paper.

Is there a way to make it self-sealing without tape?

Yes, the tuck itself holds it closed, but you can also apply a small piece of double-sided tape inside the top flap before tucking for extra security.

Sources: Origami Resource Center. Menus and buttons can differ slightly by version. Spotted something out of date? Tell us.