LetterAgent
Mail physical letters by just asking your AI assistant.
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Put the apartment number on the same line as the street address, after it: "123 Main St Apt 4B" (or "#4B" or "Unit 4B"). Don't put it on the name line or the city line, where sorting equipment can miss it. In Canada the same rule holds. LetterAgent's address check reads the full address, so include the unit.
| Designator | Example | When to use it |
|---|---|---|
| Apt | 123 Main St Apt 4B | Apartments; the clearest choice and the one sorting equipment reads best |
| Unit | 123 Main St Unit 4B | Condos, townhouses, and commercial units |
| Ste (Suite) | 123 Main St Ste 200 | Offices and businesses; avoid for residences |
| # | 123 Main St #4B | Common in handwriting, but a bare # can confuse automated readers |
| Fl (Floor) | 123 Main St Fl 3 | Large buildings where the floor is the meaningful unit |
USPS's addressing standard puts the unit designator on the same line as the street address, separated by a space. If the line gets too long, the unit can go on its own line directly below the street line, but never above it and never merged with the recipient's name. Automated sorters read the address block from the bottom up, so the street-and-unit line must sit directly above the city, state, and ZIP line.
Three mistakes cause most apartment-number delivery failures. First, putting the unit on the name line ("John Smith Apt 4B"): the name line is for names, and the unit gets treated as part of the name and ignored. Second, using only a "#" with no designator, which optical readers sometimes misread as part of the street number. Third, leaving the unit off entirely because "the carrier knows me": carriers change routes, substitutes cover sick days, and a missing unit on a 200-unit building means your mail goes back.
The same principle: unit designator after the street address on the same line, as in "123 Main St Apt 4B" followed by the city, province, and postal code. Canada Post wants the postal code on the same line as the city and province, with two spaces between the province and the code, like "TORONTO ON M4B 1B3". As with USPS, keep the unit off the name line and include it every time: apartment buildings are exactly where missing units cause the most returns.
LetterAgent verifies the recipient's address when the letter job is created, and the full address, unit included, shows through the envelope's address window. Include the apartment, unit, or suite number in the address you give your AI assistant, exactly as it should appear. A missing unit is one of the most common reasons letters come back, and it is the easiest to prevent.
Ready to mail it? Send your letter with LetterAgent - describe it to your AI assistant, approve the exact quoted price, and it's 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