I get asked this so much I decided to add a size chart and Envelope Guide
C5 Card is an A4 Card Scored on the A4 half fold When folded in half it becomes a C5 Card = C5 Envelope
Half an A4 sheet now becomes an A5 sheet, measuring 21cm by 15cm Score on the A5 Half-fold line. when folded in half. it is called a C6 Card =
C6 Envelope
To make a DL card.
Cut a sheet of A4 card 21cm by 21cm score it on the A4 Tri-fold line. = DL envelope
The small piece of card you cut from the A4 card to make the DL card, can now make a small Sq card, score it on the A5 half fold line, and you have a 10 cm by 10 cm card.= 4 - 1/2 inch Sq envelope
Gate -folds
To make a C6 Gate-fold,
Cut an A4 sheet in half, and score it on the A5 Gatefold line turn card over
and score again on the A5 Gate-fold line.
To make a C5 Gate-fold, score
a sheet of A4 card it on the A4 Gate-fold line turn card over and score again
on the A4 Gate-fold line.
Make sure you give all scored lines a nice tight crease with a bone folder.
Here is a link to a tutorial on how to line an envelope with fancy paper to make it expensive looking, well worth the time, if you choose a matching background from the cards, it will compliment it nicely HERE
