what size card fits in a4 envelope
C4 envelopes are 229 x 324 mm in size and a A4 card blank can fit inside or an A3 card blank folded in half. These C4 envelopes are ideal for sending A4 documents or certificates. C5 envelopes are 162 x 229 mm in size and fit an A5 card blank or A4 card blank folded in half.