Below is a chart of how many stamps are required for different envelope sizes (all under 20mm thickness).
As standard, Design Mummy provides 130mm x 190mm envelopes for Wedding Invitations and C6 envelopes for RSVP and Birthday invitations.
|Envelope Size||Postage Stamps Required|
|11B Envelope (145mm x 90mm)||1 postage stamp|
|C4 Envelope under 250g (324mm x 229mm)||3 postage stamps|
|C4 Envelope under 500g (324mm x 229mm)||5 postage stamps|
|C6 Envelope (162mm x 114mm)||1 postage stamp|
|5″ x 7″ Envelope (includes 130mm x 190mm Invitation iFlap Envelope)||1 postage stamp|
|C5 Envelope (229mm x 162mm)||2 postage stamps|
|DL Envelope (220mm x 110mm)||1 postage stamp|
|Reply Envelope (130mm x 80mm)||1 postage stamp|
|Square Envelopes (any size)||2 postage stamps|