USPS Mailbox Requirements: The Complete Guide
Installing or replacing a mailbox? Here are the official USPS requirements for residential mailbox height, placement, and style. Following these rules ensures your mail carrier can deliver efficiently and you won't face fines or mail service interruptions.
Mailbox Height Requirements
41" to 45"
from road surface to bottom of mailbox
- Measure from the road surface, not the ground at the post base
- Measure to the bottom of the mailbox door opening
- If on a hill, account for the road grade when measuring
- This height allows carriers to reach from their vehicle
Distance from Curb/Road
6" to 8"
from curb edge to front of mailbox
- Measure from the curb edge if you have a raised curb
- If no curb, measure from the road edge
- The mailbox should be close enough for the carrier to reach
- But not so close it gets hit by passing vehicles or snow plows
Post/Support Requirements
The Federal Highway Administration recommends supports that are sturdy but will bend or break away if hit by a vehicle:
- Recommended: 4" x 4" wooden post (treated lumber)
- Alternative: 2" diameter steel or aluminum pipe
- Post depth: Bury no more than 24" deep
- Avoid: Heavy metal pipes, concrete posts, brick columns, or anything unyielding
Safety note: Overly sturdy supports can be dangerous to vehicle occupants in a collision. Brick mailbox structures require special engineering.
Mailbox Style & Size
The USPS approves standard mailbox sizes:
| Size | Length | Width | Height |
|---|---|---|---|
| T1 (Small) | 18.5" | 5" | 6" |
| T2 (Medium) | 19" | 6.25" | 7" |
| T3 (Large) | 22.5" | 8" | 11.5" |
Look for mailboxes with the "Postmaster General Approved" stamp.
Address Number Requirements
- Numbers must be at least 1 inch tall
- Use contrasting colors (visible from the street)
- Place on both sides of the mailbox if on a through road
- Include full street address if mailbox is on a different street than your home
What's NOT Allowed
- Advertising on mailbox or post (except for "Approved by Postmaster General" marks)
- Locks that prevent carrier access
- Non-approved mailbox designs (without local postmaster approval)
- Blocking access with landscaping, vehicles, or obstacles
Quick Reference
- Height: 41-45" from road
- Setback: 6-8" from curb
- Post: 4x4 wood or 2" pipe
- Post depth: Max 24"
- Numbers: Min 1" tall
Need a USPS-Compliant Installation?
All Nice Mailbox installations meet federal USPS requirements.
Call (248) 535-0405Frequently Asked Questions
What is the correct height for a mailbox according to USPS?
The bottom of the mailbox (or mail slot) should be 41 to 45 inches above the road surface. This height allows mail carriers to easily access the mailbox from their vehicle.
How far should a mailbox be from the curb?
Mailboxes should be 6 to 8 inches back from the curb or road edge. If you don't have a raised curb, contact your local post office for specific guidance on placement.
Do I need USPS approval for my mailbox?
Mailboxes with the Postmaster General's seal of approval meet USPS standards. If you use a custom-built mailbox, you should get approval from your local postmaster before installation.
What happens if my mailbox doesn't meet USPS requirements?
Your mail carrier may leave a notice requesting corrections. In some cases, mail service could be suspended until the mailbox meets requirements. The postmaster can provide specific guidance for your situation.
Need USPS-Compliant Installation?
All Nice Mailbox installations meet federal requirements