A letter rate applies only when the sealed item stays within the service's letter format. Check the current An Post limits and rate rather than assuming every envelope counts as a letter.
Use the packed envelope's length, width, thickness and weight. Extra inserts, cards, keys or rigid contents can make an envelope too thick or unsuitable for ordinary letter processing.
Measure the sealed envelope
Avoid loose or sharp contents
Move up a format when any limit is exceeded
Choose domestic or international postage
Domestic, European and other international letters use different postage. The delivery address determines the route, so check the current official table for the destination before applying stamps.
Use the complete country name abroad
Add an Eircode for Irish addresses where available
Do not mix old assumptions with current rates
Decide whether ordinary post is enough
Ordinary letter post is designed for routine mail and should not be treated as tracked. For legal, valuable or time-sensitive documents, compare registered or express options and read their evidence and cover terms.
Routine correspondence: standard letter service
Proof requirement: registered service
Urgency: compare current express options
Address and seal it
Write a legible delivery address on the front, keep the return address separate, and attach postage in the correct area. Seal every edge so machinery cannot catch an open flap.
Use a clear, dark address
Include the destination postcode or Eircode
Keep tape away from stamps and barcodes
How to get it right
Seal the letter: Finish packing before measuring.
Check the format: Compare weight and dimensions with the current letter limits.
Select the route: Choose domestic, Europe or the relevant international destination.
Apply postage: Use the current rate and post through an accepted An Post channel.
Official sources
Rules, availability and rates can change. Confirm the live details before buying postage.