What is Address Line 2?
Complete guide with real-world envelope examples and checkout form rules.
Address Line 2 is an optional field on shipping and checkout forms used for secondary address details like apartment numbers, suite numbers, unit numbers, floor levels, or building names. If you live in a single-family house, you should leave Address Line 2 completely blank.
✓ Key Rules at a Glance
- Used exclusively for secondary unit details (Apt, Suite, Unit, Floor, Dept, Building).
- Always optional — leave it empty if you do not have a unit number.
- Do NOT put your City, State, ZIP code, or Country in Address Line 2.
- If a form rejects an empty Address Line 2, you can enter 'N/A' or combine it into Address Line 1.
Online Store Logistics
100 Fulfillment Way
Seattle, WA 98101
Destination Address
Jane Doe
742 Evergreen Terrace
Apt 4B Address Line 2 (Apartment / Unit)
Springfield, IL 62704
UNITED STATES
What Should You Put in Address Line 2?
Address Line 2 is specifically designed to store secondary location indicators that help mail carriers find your specific door within a larger property or complex. Here are the most common details to enter:
- Apartment Numbers:
Apt 4B,Apartment 12 - Suite Numbers (Offices/Businesses):
Suite 300,Ste 10B - Unit Numbers:
Unit 5 - Floor / Level:
3rd Floor,Level 2 - Building / Tower Name:
Building C,Tower 1 - Department / Attention line:
Attn: Accounting,Dept 402 - P.O. Box (if street address is in Line 1):
PO Box 123
Can You Leave Address Line 2 Blank?
Yes! In fact, most people should leave Address Line 2 blank.
If your residence or business is a standalone building with its own house number (such as a single-family home or dedicated storefront), you do not have a secondary unit number. Leaving Address Line 2 empty is the standard and expected practice.
⚠️ What if the checkout form says Address Line 2 is required?
Some poorly designed checkout forms mistakenly set Address Line 2 as mandatory. If the form blocks you from submitting, simply enter N/A (Not Applicable) or a single period (.).
❓ Frequently Asked Questions
What is the difference between Address Line 1 and Address Line 2?
Address Line 1 is for your primary street address (house number and street name). Address Line 2 is for secondary sub-unit information such as apartment, suite, unit, or floor numbers.
Does PO Box go in Address Line 1 or 2?
If you are using a PO Box as your primary delivery address, put 'PO Box 123' in Address Line 1. If you provide both a physical street address and a PO Box, put the street address in Line 1 and PO Box in Line 2.
Check Country-Specific Address Rules
Select a country to view official postal line layouts, required fields, and postcode formats:
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