There are two main categories of lettermail weights and sizes to help determine how much it will cost to send your item.
Standard lettermail (50 g or less)
Use a single stamp for items that are within the standard weight and size range.
Minimum dimensions
140 mm x 90 mm (5.5 inches x 3.5 inches)
Maximum dimensions
245 mm x 156 mm (9.6 inches x 6.1 inches)
Please note: maximum dimensions for cards and postcards to the U.S. or an international destination are 235 mm x 120 mm (9.2 inches x 4.7 inches).
Non-standard and oversize lettermail (0 to 500 g)
Oversize or non-standard size envelopes and postcards will cost more in postage.
Minimum dimensions
140 mm x 90 mm (5.5 inches x 3.5 inches)
Maximum dimensions
380 mm x 270 mm (15 inches x 10.6 inches)
If your mail exceeds 500 g
If your letter exceeds 500 g you will have to use our Parcel Services.