How to Fold an Envelope: Easy Step-by-Step Guide

What You’ll Need

A rectangular sheet of paper (standard 8.5 x 11 inch or A4 works best)
A flat, clean surface
Optional: a bone folder or the edge of a ruler to make crisp creases

Step-by-Step

Start with the paper face down. Place the sheet on your work surface with the side you want on the inside of the envelope facing down. If you’re sending a letter, the writing should face up.
Fold the bottom edge up. Bring the bottom edge up to meet the top edge, but do not crease yet. Instead, only pinch the center to mark the midpoint, then unfold. This gives you a reference line.
Fold the bottom third up. Using the center pinch as a guide, fold the bottom edge up so it reaches about one-third of the way up the sheet. Crease firmly. This forms the bottom flap that will hold the contents.
Fold the top edge down. Bring the top edge down to meet the bottom fold you just made. Crease well. You now have a long, narrow rectangle.
Fold the left corner in. Take the top-left corner of the rectangle and fold it down diagonally so its edge aligns with the center crease. The fold should create a triangle at the top left.
Fold the right corner in. Repeat on the top-right corner, folding it down diagonally to meet the center crease. The two triangles should meet in the middle, forming a pointed top.
Tuck the top point down. Fold the entire pointed top section down along the line where the two triangles meet. This creates a flap that will tuck into the bottom pocket.
Insert the flap into the pocket. Slide the pointed flap into the opening at the bottom of the envelope. Press down to seal the tuck. Your envelope is complete.

Common Mistakes

Uneven folds: If your folds are not straight, the envelope will be lopsided and the flap may not tuck in cleanly. Always line up edges carefully before creasing.
Skipping the center pinch: Without a reference mark, it’s easy to misjudge the one-third fold, leading to a flap that’s too short or too long.
Creasing too lightly: Soft creases make the paper spring back, so the tuck won’t hold. Use firm pressure or a bone folder.
Folding the wrong side: If you fold with the writing side facing down, the writing will end up on the outside. Always start with the side you want hidden facing down.

Tips

Use a sheet that is slightly larger than the contents you plan to place inside, so the paper doesn’t bulge.
If you want a more secure closure, add a small piece of tape or a sticker to the flap after tucking.
For a more decorative envelope, use patterned paper or add a washi tape seal.
Practice with scrap paper first to get the technique down before using your good stationery.

Troubleshooting

The flap won’t stay tucked: This usually means the folds are too shallow. Refold with sharper creases, or use a slightly heavier paper.
The envelope is too small for the contents: You need a larger starting sheet. The final envelope is roughly one-third the height of the original paper.
The corners don’t meet in the middle: Make sure you are folding the corners at the same angle. Adjust the diagonal folds so the edges align with the center crease.
The paper tears: If the paper is thin or dry, it may tear at the crease. Use a lighter touch when creasing, or choose a thicker paper.

Frequently Asked Questions

Can I use any size paper?

Yes, any rectangular sheet works. The final envelope will be about one-third the height of the original, so adjust the paper size based on what you want to mail.

Will this hold a standard greeting card?

Yes, if the card is smaller than the envelope’s pocket. Fold the card in half if needed, but ensure it fits without bulging.

Do I need tape to keep it closed?

No, the tuck holds it closed. However, for mailing, a small piece of tape is recommended to prevent the flap from opening in transit.

Can I write the address on the envelope?

Yes, write the address on the side that is now the front (the side that was originally face down). It’s best to write before folding, but you can write on the flat surface after folding.

What if my paper is square?

Square paper will produce a wider, shorter envelope. The folds still work, but the proportions will differ. For a classic envelope, use a rectangle.

Is this method secure for mailing?

For casual notes, yes. For official mail, use a proper envelope with adhesive. This method is more for personal use or when you’re in a pinch.

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