Royal Mail size guide
Royal Mail large letter size
The maximum published dimensions are 353mm × 250mm × 25mm, with weight up to 750g.
353 × 250 × 25 mm
Maximum weight: 750g
Measure the packed item, including its envelope, mailer, padding and tape. A few millimetres of extra thickness can move an item into the next format.
Royal Mail’s current size guide ↗
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