When you're addressing mail or packages, getting the street numbers and unit identifiers right makes all the difference in whether your mail actually arrives. Below’s a straightforward guide to formatting addresses correctly as of 2026. Whether you're mailing a birthday card to a friend or shipping a gift to family overseas, these rules keep postal services from scratching their heads over your address.
Quick Fix Summary: Put the recipient’s name on the first line, the street number and name (plus unit number if there is one) on the second line, and the city, state, and ZIP code on the third. Only abbreviate terms like St., Ave., or Blvd. when they’re part of a full address. Unit identifiers such as Apt 3B or #42 should sit right next to the street address.
What’s the big deal about street number formatting?
Proper formatting isn’t just about neatness—it keeps your mail moving. Slip up by leaving out a unit number or jamming the ZIP code in the wrong place, and your package might end up in the wrong city or, worse, get sent back. As of 2026, postal services in the U.S. and plenty of other countries depend on standardized layouts to handle billions of pieces of mail every single day. International addresses need even more care, with country names and postal codes following the local rules to a T.
How do I format a street address correctly?
Here’s exactly how to break it down:
- Line 1: The full name of who’s receiving the mail. If it’s a business, toss the company name on this line too.
- Line 2: The street number, street name, and unit number if there is one. Use abbreviations like St., Ave., or Blvd. only when they’re part of a complete address. For example:
- 1234 Maple St., Apt 4B
- 567 Oak Ave #22
- Line 3: City, state, and ZIP code (or the postal code for international addresses). For U.S. addresses, use the two-letter state abbreviation (think CA for California) followed by the five-digit ZIP code. When mailing overseas, slap the country name in all caps on the very last line.
Here’s what a properly formatted U.S. address looks like:
| Line | Content |
|---|---|
| 1 | Alex Johnson |
| 2 | 789 Pine Blvd, #12 |
| 3 | Springfield, IL 62704 UNITED STATES |
Why is my mail still getting returned or sent to the wrong place?
If your mail keeps bouncing back or landing in the wrong mailbox, here’s where things usually go wrong:
- Unit Number Oversight: Make sure the unit number (like Apt 3B or #42) sits on the same line as the street address. If it’s missing, your mail might wander around a big apartment building for days.
- ZIP Code Mix-Ups: Even a single digit wrong can reroute your package to Timbuktu. Use the USPS ZIP Code Lookup Tool to confirm the right code before you seal that envelope.
- International Address Headaches: Every country has its own quirks. In the UK, for example, the postcode goes on a separate line after the city. Need help? The Royal Mail’s address finder spells out exactly how to format addresses for the UK.
What’s the easiest way to avoid address mistakes?
Nobody wants to deal with lost or delayed mail, so here are some habits that save time and headaches:
- Run it through a validator: Shipping carriers like UPS, FedEx, and DHL have free tools that check your address for typos and formatting issues before you print that shipping label.
- Keep your address current: Moved recently? Changed apartments? Update your address with banks, subscriptions, and any service that sends you mail. Otherwise, you’ll keep getting “return to sender” notices for mail addressed to your old place.
- Always add a return address: Slap your name and address in the top-left corner of the envelope or package. That way, if the mail gets misrouted, it can find its way back to you instead of disappearing into the void.
- Proofread like it’s a term paper: Addresses don’t care about capitalization, but they’re brutal about spelling. Double-check every street name, unit number, and ZIP code. One typo can send your package on a detour you didn’t sign up for.
