LetterAgent
Mail physical letters by just asking your AI assistant.
Home > Guides > Collection box rules
Blue collection boxes take stamped letters, postcards, and flat mail of any normal size. Parcels over 13 ounces with stamp postage cannot go in: aviation-security rules require those to be presented at a retail counter. Check the pickup-time label on the box so your mail does not sit until the next collection day.
| Item | Can it go in the box? | Notes |
|---|---|---|
| Stamped letters and postcards | Yes | The box's main job; any size that fits the slot |
| Metered mail and prepaid flats | Yes | As long as postage is fully paid |
| Small parcels under 13 oz with stamps | Yes | Lightweight stamped packages are fine |
| Parcels over 13 oz with stamps | No | Must be handed over at a retail counter |
| Registered or certified mail | Technically yes, but not recommended | You lose the counter receipt; hand it to a clerk instead |
| International letters | Yes | Fully stamped international mail goes in like domestic |
It is an aviation-security rule, not a postal whim. Mailpieces over 13 ounces that carry only stamps could, in theory, be placed anonymously by anyone, so the Postal Service requires them to be presented in person at a retail counter, where the sender's identity is on record. Parcels with postage printed online (Click-N-Ship labels, postage from a shipping service) are exempt from the 13-ounce rule because the sender is already identified through the account. So the same 2-pound box is refused with stamps but fine with a printed label. If you have been dropping heavy stamped parcels into the box, some of them may have been pulled out and returned to you for exactly this reason.
Every box carries a label listing collection times by day of the week. Mail dropped in before the listed time goes out that day; mail dropped in after sits in the box until the next scheduled pickup, which can mean Sunday mail waiting until Monday morning. Boxes in front of post offices usually have the latest pickup times in an area, so if you miss the neighborhood box, the post office box is worth the detour. Two details people miss: holidays shift the schedule (a federal holiday means no collection), and some boxes have separate slots or listed times for Express Mail with a later cutoff.
Canada Post uses red street letter boxes for the same purpose: stamped lettermail and light parcels go in, and pickup times are posted on the box. Canada does not have the exact 13-ounce counter rule, but oversized parcels that do not fit simply do not belong in the box and should go to a retail outlet. One Canadian quirk: in many neighborhoods, community mailboxes replaced door-to-door delivery, and those boxes include an outgoing-mail slot, so the "collection box" for a lot of Canadians is the same box they get their mail from.
Ready to mail it? Send your letter with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it is printed and mailed.
LetterAgent is a working name. Prices include print, postage, and our service fee. US prices in USD, Canadian prices in CAD (Canadian prices exclude applicable sales tax, added at checkout). Currently in private testing.
Need help? Ask your assistant: it can check a job's status any time. If it ever can't handle something: hello@getletteragent.com