Letterbox Standards in Australia

Did you realise there are letterbox standards for minimum mailbox sizes in Australia? And also for where to position various types of letterboxes?

You certainly wouldn't know it from a quick look up and down most streets! However, when you think about it, it makes sense.

As part of its terms and conditions of service Australia Post includes an appendix detailing letterbox standards for size, numbering and  placement of your mailbox. If you don't provide a mailbox that is large enough to receive the anticipated volume of standard letters, or if your mailbox isn't easily accessible your postie may refuse to deliver your mail. I suspect this doesn't happen often, but it's better to be safe than sorry!

I believe the Australia Post standard is derived from the Australia New Zealand official standard, AS-NZS 4253-1994. If you make letterboxes to sell in Australia I recommend you purchase this standard to make sure you conform.

And, before you buy, make or install your next letterbox make life easier for your postie by conforming to the Australia Post standard. You'll also be helping make your mail delivery service speedy and reliable.

I've summarised the letterbox standards for most residential mailboxes below. Please check the original Australia Post Standards and the Australian Standard for full details.

Mailbox Sizes

letterbox standards

Sensibly, the Australia Post recommendation is to have the right size letterbox for the amount and type of mail you typically receive. If your household orders small packages online you should factor this into your choice of letterbox.

The picture to the left illustrates an example of the minimum letterbox specifications for a single residential mailbox. They are...

  • The delivery opening as a minimum should take a C4 envelope (229mm x 324mm) -- this is suitable for A4 content. It should not be easy to remove mail through the delivery opening
  • The delivery opening should be at least 230mm x 30mm and...
    • For horizontal openings: 130mm above the base of the internal space
    • For vertical openings: 40mm above the base of the internal space
  • The minimal internal dimensions should be 230mm x330mm x 160mm. According to the Australian Standard it doesn't matter which orientation.
  • There should be an access door for easy removal of delivered mail

Mailbox Numbering

All boxes should have street numbers or apartment numbers prominently displayed on the front of the box (the side where the delivery opening is) below the delivery opening.

Mailbox Placement

The aim is to allow the postie to deliver mail without having to get off his or her bicycle or motorbike...

  • Single boxes should be installed so that the bottom of the delivery opening is between 900mm and 1200mm above the ground
  • Nests of boxes should be installed so the openings are within 600mm to 1600mm above the ground
  • The box should be positioned in clear view at the junction of the boundary of your property and your driveway or footpath
  • The delivery opening should face the road, driveway or footpath and be easy to access (not blocked by shrubs etc)

Other Considerations

  • Your mailbox should be weather resistant -- it may be sensible to have a mailbox flap (that opens inwards and is easy to open) or hood over the delivery opening to protect mail from rain. Make sure it doesn't make the opening narrower than 30mm.
  • If you want to  lock your mailbox make sure there's the ability to install a lock on the access door
  • It's a good idea to have a separate holder for newspapers and non-mail items