Make a paper envelope that fits your card

Make a flat envelope from one rectangular piece of paper. Two side tabs join the front to the body; the top flap stays free until your card is inside. This worked example also gives a formula for another card size.

By Coru · Published 2026-10-24 · Updated 2026-10-24

Start with the card

Measure the card as it will go inside: close a folded card first. Our example is 150 mm wide and 100 mm high. Make a nominal 160 × 110 mm envelope, leaving 10 mm extra in each direction. That is 5 mm per side when the card is centred, not 10 mm per side.

Use ordinary paper, a ruler, pencil, scissors and a glue stick suitable for paper. A 190 × 250 mm rectangle is enough for this example; cut it from a larger sheet. Try scrap paper before using a decorated sheet. This flat design is for a card or note handed to someone, not a bulky gift. Help children with cutting as needed.

1. Mark a rectangle and two levels

Place the 190 mm edge across the top and the 250 mm edge down the side. Work with the side that will be inside facing up. All distances below start from the original top or left edge, not from the previous mark.

Draw vertical lines 15 mm and 175 mm from the left edge. Between them is a 160 mm central column. Draw horizontal lines 30 mm and 140 mm from the top. The central column now contains a 30 mm closure flap, a 110 mm body panel, and a 110 mm front panel.

The two 15 mm side strips beside the BODY become glue tabs. The side strips beside the closure flap and front panel are waste. Mark those four waste rectangles with crosses before cutting.

Flat layout: measurements in millimetres

text

                 15       160       15
Top, y = 0     +----+-------------+----+
               |CUT | CLOSURE 30  |CUT |
     y = 30    +----+-------------+----+
               |TAB |  BODY 110   |TAB |
               | 15 |             | 15 |
     y = 140   +----+-------------+----+
               |CUT | FRONT 110   |CUT |
     y = 250   +----+-------------+----+
                x=0 15          175  190

Diagram is schematic, not a printable template. CUT means remove that whole rectangle. Fold lines are specified in step 2; do not cut the central column apart.

2. Cut four corners, then crease

Remove two 15 × 30 mm rectangles at the top corners and two 15 × 110 mm rectangles at the bottom corners. Stop each cut at its marked intersection. Keep the entire central column and both side tabs attached.

Fold each side tab inward along the body’s vertical edge. Crease only between the 30 mm and 140 mm levels. Fold the front panel upward along the 140 mm line; its free edge should meet the 30 mm line. Fold the closure down along the 30 mm line. Use your fingers to press each crease, then open the front and closure again.

3. Check the fit before glue

Keep the inside of the body facing up. Lay the card on it, with about 5 mm space at every edge. Fold the tabs over the card’s sides and the front panel up over them. The card should slide out at the top without bending. The closure should fold over the front panel.

Remove the card. If the trial is tight, check the measurements and straightness of the folds. If the card has thick layers or raised decorations, make a larger scrap-paper version. The 10 mm allowance is a starting choice for this flat example, not a fit guarantee for every card.

4. Join the front to the tabs

Keep the tabs folded inward and the front panel open. Apply a thin layer of glue to the upper, exposed face of each tab. Slide scrap paper under a tab while applying glue, then remove the scrap. Keep glue off the body underneath: that surface must stay separate so the card can enter.

Fold the front up and press it onto both glued tabs. Check that its top edge meets the base of the closure. Leave the closure open and let the adhesive dry as directed on its packaging. Do not put the card into wet glue.

Insert the card between the body and the folded tabs/front assembly. Fold the closure down over the outside. A small piece of removable tape can hold it for hand delivery; test the tape on a scrap if you want to reopen it neatly.

If something goes wrong

The pocket is glued shut: glue reached the body. Do not force the card inside; make a fresh version and protect the body with scrap while gluing each tab.
The card catches at one side: open the closure fully and guide the card behind both tabs, not between a tab and the front. Check for squeezed-out glue.
The front finishes too high or too low: reopen before gluing and check the 140 mm crease. The lower panel must be 110 mm high.
A tab separates: remove the card, check that the glue suits your paper, reglue the joint and let it dry. Coated decorative paper may need a different paper adhesive.

Resize the same construction

For another flat card, call its width W and height H. Start with body width B = W + 10 mm and body height D = H + 10 mm. Keep 15 mm side tabs and a 30 mm closure. The starting rectangle is (B + 30) mm wide and (2D + 30) mm high.

Mark the vertical lines at 15 and 15 + B mm, and horizontal lines at 30 and 30 + D mm. Remove the four corner rectangles as before. Check that the whole rectangle fits your paper; rotating the card can change whether it fits. Always try the actual card before gluing.

About this pattern

RBE’s assembly guide shows the general sequence of folding the side tabs inward, applying glue and bringing the bottom panel up. Coru created these dimensions, layout, fit check and troubleshooting instructions. The measurements and ideal fold geometry were checked digitally; no physical trial of this particular pattern was performed.

Sources & further reading

RBE — envelope assembly instructions