The international standard for identifying postal items
17 comments
·June 12, 2025Ecco
Scoundreller
What helps is that they don’t ship direct from China by mail much. They often send in bulk to the destination country and then mail locally, and local post systems can have their own domestic format.
Or they have their own private courier do the last mile delivery too so it never touches any postal operator.
bravesoul2
Do they? In Australia usually get them direct from HK or China because it is cheaper to do that even than post it within Australia!
wombatpm
Service type and serial need to be unique. Countries control what that 2letter field means. There is no rule against multiple codes indicating the same service. So AA through AZ would give you 260,000,000 unique combinations that you shouldn’t reuse for 1 year. Rinse, later and repeat if you need more.
Sharlin
Yeah. Apparently last year they shipped over two million small parcels to Finland (pop. 5.6M) alone, which is completely bollocks.
mongol
And I wonder what was the constraint to not make it longer when they developed the standard. Making it a few digits more seem it wouldn't cost much.
benced
Even the US must easily run into this constraint.
xattt
You could hate it by an internal metric, like date received.
nojs
I’m surprised this article didn’t mention the LPC code [1]
forth_fool
Isn't 8 digits closer to 100 million unique numbers than to 10?
akpa1
Author here - yep! It is, that was a typo in the article.
notpushkin
It’s exactly 100 million unique numbers.
bloak
Does that complex algorithm for the check digit have any advantage over the much simpler algorithm used for EANs or 13-digit ISBNs?
With a limit of 10 million different serial numbers, I wonder how China does it. I can't come up with a decent estimate, and maybe I'm way off. But with the growth of sellers like Shein or Temu, I wouldn't be surprised if they shipped that many parcels in like a single day ? Or at least in a timeframe short enough that they would have over 10 million shipped but yet-to-be-delivered parcels, effectively running out of tracking numbers.