United States Postal Service Mailbox Regulations and Specifications
4C Centralized Mailbox Regulation Information
How the US Postal Service STD-4C Regulation affects Centralized Mailbox Selection
– standard required for new construction (effective October 2006)
US Postal Service STD-4C Specification Information
– applies to 4C Horizontal Mailboxes (specifications 4C mailboxes must meet)
Commercial Mailbox Guidelines for New Construction and Replacement
Guidelines for Upgrading or Replacing Your Commercial Mailboxes
Americans with Disabilities Act (ADA) Information
ADA Compliance Guidelines-for 4C Horizontal Mailboxes
United States Postal Service Information
For new construction and replacement information of existing equipment
USPS National Delivery Planning Standards (PDF)
– includes 1 parcel locker to every 5 mailbox compartments requirement (1:5 ratio) – see page 13 (effective July 2020)
USPS Mailbox Height Regulations for Installing Commercial Mailboxes
Commercial mailboxes for U.S.P.S. delivery include Cluster Box Units (CBU’s), 4C Horizontal Mailboxes, 4B+ Horizontal Mailboxes and 4B+ Vertical Mailboxes. These products are commonly used in apartment complexes, commercial buildings, residential developments, condominiums and several other applications.
4C Horizontal Mailboxes must be installed according to postal regulations including the mailbox height requirements listed below:
67”- The tenant lock in the highest mailbox shall be no more than 67” above the finished floor.
48”- The USPS Arrow lock (master door lock) opening shall be no more than 48” above the finish floor. In compliance with ADA regulations, the high forward and high side reach shall be a maximum of 48” above the finished floor.
36”- The USPS Arrow lock (master door lock) opening shall be a minimum of 36” above the finished floor.
28”- The floor of the lowest tenant mailbox shall be no less than 28” above the finished floor.
15”- The floor of the lowest parcel locker shall be no less than 15” above the finished floor. In compliance with ADA regulations, the low forward and low side reach shall be a minimum of 15” above the finished floor.