An apartment address has two jobs: identify the building and identify the unit. The street line does the first; the unit line does the second.
US format
Write the street first, then the unit on line 2: 123 Main Street, Apt 4B, Springfield, IL 62704. “Apt”, “Unit”, “Suite”, and “#” are all common; pick one and stay consistent.
International format
In Germany, the house number often follows the street and the unit may be written as “Wohnung 4B”. In Japan, the building and room go after the block address. Check the country format before you rearrange the line.
Common errors
Do not put the unit number in the city field. Do not omit the unit when the building has multiple units. Do not use a comma to separate the unit if the form already has a unit field.
Questions
- Yes for most US carriers. Use the label the building uses so the courier can match it.
- On the unit line: “Floor 3” or “3rd Floor”. If the building uses a room number, include it after the floor.
Is “Apt 4B” the same as “Unit 4B”?+
Where does the floor go?+
Examples are synthetic. Do not use a generated address for identity checks, account registration, or delivery.