The basic format that works almost everywhere

A properly typed address has four lines: the recipient's name, the street address, the city and state with ZIP code, and the country if it's going international. Each line goes on its own row. The street address is the line that trips people up most — it needs the house or building number first, then the street name, then any apartment or suite number.

Here's what it looks like in practice:

Sarah Chen 427 Maple Avenue, Apartment 3B Portland, OR 97214 USA

If there's no apartment number, you skip that part. If the mail is staying within the United States, you can leave off the USA line. The key is: number first, street name second, then any unit identifier, all on one line.

Key Takeaways

  • Put the street number before the street name, and any apartment or suite number after the street name on the same line.
  • The city, state, and ZIP code go on their own line, with the state as a two-letter abbreviation and the ZIP code after a space.
  • For mail within the United States, you don't need to add the country name, but it doesn't hurt.
  • Avoid abbreviating the street name (write "Street" not "St.") unless the address label or form specifically asks you to shorten it.
  • Double-check the ZIP code against the city and state — mismatches cause delays because postal machines read the ZIP first.

When the street address has a direction or suffix

Many addresses include a direction (North, South, East, West) or a street type (Street, Avenue, Boulevard, Road). The direction comes before the street name, and the street type comes after it. So you'd write "427 North Maple Avenue" or "1200 East 5th Street", not "427 Maple North Avenue" or "1200 5th East Street".

Some addresses also have a suffix like "Extended" or "Court" instead of "Street". These follow the same rule — they come after the street name. If you're unsure whether to abbreviate (N for North, Ave for Avenue), check the original document or the recipient's own mail. Postal services prefer the full word, but many online forms auto-correct abbreviations anyway.

Apartment, suite, and unit numbers

When there's an apartment, suite, office, or unit number, it goes on the same line as the street address, after the street name. You can write it as "Apartment 3B", "Apt 3B", "Suite 200", "Unit 5", or "#3B" — all of these work. The postal service reads the main street address first, then the unit number, so the order matters but the exact format is flexible.

If you're filling out a form with separate fields for "Street Address" and "Apartment/Suite", put just the street number and name in the first field, and the unit information in the second. If there's only one address field, put everything on one line: "427 Maple Avenue, Apartment 3B".

ZIP codes and their relationship to cities and states

A ZIP code is tied to a specific geographic area, and that area should match the city and state you write. If you write "Portland, OR 97214" but the actual ZIP code for that address is 97215, mail sorting machines will catch the mismatch and may delay delivery while they figure out which one is correct. The safest approach is to verify the ZIP code against the city and state using the USPS ZIP Code Lookup tool on usps.com, or by asking the recipient directly.

Some large cities have multiple ZIP codes, and some ZIP codes span parts of different cities. This is why the ZIP code is the most reliable piece of information — it's what the postal service uses to route mail to the right delivery station. If you're uncertain whether you have the right city name, the ZIP code will tell you.

International addresses

International mail needs the country name on its own line at the bottom. The format for everything above that line varies by country. In Canada, the format is similar to the US: street address, then city, province abbreviation, and postal code, then Canada. In the United Kingdom, you'd write the street address, then the city or town, then the postcode, then United Kingdom.

The safest approach for international mail is to ask the recipient how they want their address written, or to look up the postal service's format for that country. Royal Mail (UK), Canada Post, and Australia Post all have address formatting guides on their websites. If you're mailing from the United States to another country, the USPS website has country-specific formatting rules.

Common mistakes that slow down delivery

The most frequent error is putting the street name before the number — "Maple Avenue 427" instead of "427 Maple Avenue". Postal machines read left to right and expect the number first, so this can cause a delay while the mail gets sorted manually. Another common mistake is abbreviating the street name when the form doesn't ask for it — "427 Maple Ave" when the actual street is "Maple Avenue" — which can create a mismatch in the postal database.

Mismatched ZIP codes and city names cause delays because the sorting machine has to decide which one is correct. If you write "Portland, OR 97215" but the address is actually in Gresham, OR 97030, the machine will flag it. Handwriting that's hard to read also slows things down, especially for numbers — a "5" that looks like an "8" will send mail to the wrong address. If you're handwriting an address, write slowly and make sure each number is clear.

Typing addresses into online forms

When you're filling out an address field on a website, follow the form's instructions. Some forms have separate fields for street address, city, state, and ZIP code. Others have one large text box. If the form has separate fields, put only the street number and name in the "Street Address" field, and save the apartment or suite number for the "Apartment/Suite" field if one exists. If there's only one field, type it all on one line with commas separating the major parts: "427 Maple Avenue, Apartment 3B, Portland, OR 97214".

Many websites now have address autocomplete features that suggest addresses as you type. These are usually accurate, but check the suggestion against what you actually need before you click it. If the autocomplete doesn't find the address, you may need to type it out fully or check that you have the correct spelling and ZIP code.

Frequently Asked Questions

Do I need to capitalize every word in an address?

No. Standard capitalization is fine — capitalize the first letter of street names, city names, and the first letter of apartment numbers if they start with a letter, but you don't need to capitalize every single word. "427 Maple Avenue" is correct; "427 MAPLE AVENUE" works but isn't necessary. Postal machines read addresses regardless of capitalization.

What if the street name is a number, like "5th Street"?

Write the house number first, then the street number: "427 5th Street". This is different from "427 Fifth Street" — some cities use numerals for street names and some spell them out. Check the original address to see which format is used in that area, or look it up on a map.

Should I use periods after abbreviations like "Dr." for Drive?

The USPS prefers no periods in address lines — write "Dr" not "Dr." — but most postal machines will read it correctly either way. If you're handwriting or typing into a form that doesn't specify, using periods is safe and won't cause a problem.

Can I write a P.O. Box address the same way as a street address?

No. A P.O. Box address has its own format: the recipient's name, then "P.O. Box [number]", then the city, state, and ZIP code. You don't include a street address. Example: "Sarah Chen, P.O. Box 1847, Portland, OR 97214". The ZIP code for a P.O. Box is specific to that box's location, not a street address.

What if I don't know the full ZIP code?

The city and state alone will usually get mail delivered, but it will take longer because postal workers have to look up the ZIP code manually. Use the USPS ZIP Code Lookup tool on usps.com — you can search by street address, city, or ZIP code to find the right one. Having the correct ZIP code speeds delivery significantly.