USPS PO Box cost depends on three things: the box size (Size 1 Extra Small through Size 5 Extra Large), the fee group USPS assigns to that Post Office’s ZIP Code, and the rental term (3, 6 or 12 months). There’s no single national price. To see the exact fee for a specific Post Office, search by ZIP Code on the USPS PO Boxes page, which shows every available size and term.
This guide explains each cost factor, the size tiers and what they hold, the one-time charges, how refunds work, and when you might qualify for a free box.
Table of Contents
- What determines the cost of a USPS PO Box?
- What are the USPS PO Box sizes?
- How do rental terms affect PO Box cost?
- What other charges come with a PO Box?
- Can you get a free USPS PO Box?
- What does a PO Box at a competitive location include?
- How do you check the PO Box price at your Post Office?
- Do you get a refund when you close a PO Box?
- How does PO Box cost compare with other mailbox options?
- Frequently Asked Questions
What Determines the Cost of a USPS PO Box?
The USPS Domestic Mail Manual (DMM 508.4) sets PO Box fees by two things: box size and the fee group of the box’s 5-digit ZIP Code. USPS can move a ZIP Code up or down one fee group, at most once a calendar year, based on costs and local market conditions. Your rental term then decides how much you pay at once.
- Box size: larger boxes cost more at the same Post Office.
- Fee group: the same size can cost several times more in a dense city than in a small town, because the city ZIP Code is in a higher fee group.
- Location type: USPS classifies each Post Office’s boxes as either competitive (usually busier metro locations, with extra features) or market-dominant.
- Rental term: you prepay 3, 6 or 12 months.
Because the fee group follows the ZIP Code, two Post Offices a few miles apart can charge noticeably different amounts for the same size. If convenience allows, compare nearby offices before you rent. Our USPS locations guide helps you find the Post Offices around you.
What Are the USPS PO Box Sizes?
Most Post Offices offer five sizes, though not every location has all five. Every box is about 14-3/4 inches deep. The size is usually the biggest factor in cost that you control.
| Size | Opening (in.) | What it holds (per USPS) | Good for |
|---|---|---|---|
| Size 1: Extra Small | 3 × 5-1/2 | 10–15 letters and a few rolled magazines | Personal mail and bills |
| Size 2: Small | 5 × 5-1/2 | 15+ letters, 5 rolled magazines, or 1 small Flat Rate Box | Households that get magazines |
| Size 3: Medium | 5-1/2 × 11 | Large envelopes and magazines stacked flat, plus 2 small Flat Rate Boxes | Small businesses, document mail |
| Size 4: Large | 11 × 11 | 2 shoeboxes plus 10–15 letters, or small and medium Flat Rate Boxes | Frequent small packages |
| Size 5: Extra Large | 12 × 22-1/2 | Multiple packages and parcels | Online sellers, high mail volume |
Packages that don’t fit go into a secure parcel locker, with the locker key left in your box, or they’re held at the counter. That means a smaller, cheaper box can still work if you get only the occasional package. To see what fits, compare common items: a USPS bubble mailer fits most Small and Medium boxes, while a USPS Priority Mail Shoe Box needs a Large box.
How Do Rental Terms Affect PO Box Cost?
USPS offers 3-month, 6-month and 12-month payment periods, and you can prepay up to a year ahead. Longer terms mean fewer renewals, and USPS has a sign-up incentive at competitive locations.
| Term | Auto-renewal | What to know |
|---|---|---|
| 3 months | Required, no opt-out | Not offered everywhere. No refund if you close mid-period |
| 6 months | Optional | Half the fee refunded if you close in the first 3 months |
| 12 months | Optional | New customers at competitive locations get 13 months of service for a 12-month payment |
Payment is due by the 10th of the month your term ends. If USPS hasn’t received it, the box closes on the 11th. You can renew online, at a self-service kiosk, by mail or at the counter.
What Other Charges Come With a PO Box?
Besides the rental fee, expect these smaller charges:
- Key deposit: USPS issues two keys to each new box holder, each with a refundable deposit. New customers in some competitive fee groups pay no deposit for the first two keys.
- Extra keys: additional keys carry a refundable deposit plus a non-refundable fee. If you lose a key, our guide to USPS mailbox key replacement explains the process.
- Lock changes: a lock replacement fee applies if a lock has to be changed, for example after lost keys.
Deposits come back when you close the box and return each key to the Post Office that issued it, so keep your receipt.
Can You Get a Free USPS PO Box?
Yes, in one situation. USPS offers free PO Box service, called Group E, if your physical address is inside the Post Office’s delivery ZIP Code boundaries and could receive carrier delivery, but USPS doesn’t deliver to a mail receptacle at or near it. It’s limited to one free box per delivery point, and you must apply in person rather than online.
Group E doesn’t cover individual tenants at places with single-point delivery, such as hotels or colleges, or addresses served by cluster mailboxes. If you’ve been paying for a box and later qualify for Group E, USPS may refund past fees, prorated for up to 24 months.
What Does a PO Box at a Competitive Location Include?
Competitive-location boxes often cost more, but they come with Premium PO Box Service features that can make them worth it for businesses:
- Street Addressing: use the Post Office’s street address with your box number after a “#” sign. This lets you receive packages from UPS, FedEx, DHL and Amazon at your PO Box, subject to USPS mailing standards and local availability.
- Signature on File: packages that need a signature can be placed in your box or a parcel locker instead of waiting at the counter.
- Parcel lockers: secure lockers for packages too large for the box itself.
Without Street Addressing, private carriers can’t deliver to a standard PO Box. Our guide on how to ship to a PO Box explains the address format and carrier options. Packages delivered to your box show their status in USPS Tracking, the same as home deliveries.
How Do You Check the PO Box Price at Your Post Office?
The USPS PO Boxes page shows exact fees and availability for each location:
- Go to the USPS PO Boxes page and choose “Find a PO Box Near You.”
- Enter your ZIP Code or address to see nearby Post Offices with open boxes.
- Select a location to see each size’s fee for 3, 6 and 12 months.
- Reserve online, then bring the printed form and two acceptable IDs to that Post Office within 30 days to pick up your keys.
You can also apply at the counter with PS Form 1093 and two forms of ID: one primary photo ID and one secondary ID that ties you to your address. Our step-by-step guide on how to get a PO Box covers the application, ID rules and waitlists in detail.
Do You Get a Refund When You Close a PO Box?
Sometimes. On a 6-month term, USPS refunds half the fee if you close the box within the first 3 months, and nothing after the fourth month begins. If you’ve already prepaid the next period, that whole payment is refunded. Closing during a 3-month auto-renewal period earns no refund.
Close the box online through Manage PO Box or at the Post Office, return both keys to get your deposits back, and file a USPS change of address so mail still sent to the box gets forwarded.
How Does PO Box Cost Compare With Other Mailbox Options?
A USPS PO Box is usually the lowest-cost private mailing address, but it has limits. A private mailbox (PMB) at a retail mailbox store gives you a street address and accepts packages from any carrier without Street Addressing. Virtual mailboxes add mail scanning.
| Option | Street-style address | Packages from UPS and others | Who sets the price |
|---|---|---|---|
| USPS PO Box | Only with Street Addressing | Only with Street Addressing | USPS fee group and size |
| Private mailbox (PMB) | Yes | Yes | The individual store |
| Virtual mailbox | Yes | Yes, with scanning | The service provider |
Our guide to private mailbox rental covers how PMBs work. Whichever you choose, the box only receives mail. To send it, drop letters in a USPS collection box and ship packages from your account.
What Can You Receive at a USPS PO Box?
A PO Box accepts every USPS mail class. That includes books sent by USPS Media Mail, packages by Priority Mail or First-Class Mail versus Priority Mail, and legal correspondence by Certified Mail. For a Certified Mail piece, USPS leaves a notice in your box for pickup unless you’ve set up Signature on File. If you send legal notices yourself, our guide on how to send certified mail walks through the forms.
Running a small business that ships with USPS? A PO Box handles incoming mail. For outgoing packages, ParcelPath gives you discounted USPS postage of up to 89% off retail, free to use. Compare prices for your next package in the ParcelPath rate calculator. For more on every USPS service, see the USPS shipping guide or browse all carriers on our shipping companies page.
Frequently Asked Questions
How much does a USPS PO Box cost per month?
USPS doesn’t publish one monthly price. The cost depends on box size, the fee group of the Post Office’s ZIP Code, and whether you prepay 3, 6 or 12 months. Search your ZIP Code on the USPS PO Boxes page to see exact fees, and compare a few nearby Post Offices, since fee groups can differ.
What is the cheapest USPS PO Box size?
Size 1 (Extra Small), with a 3 × 5-1/2 inch opening, is the lowest-cost box at any Post Office. It holds about 10 to 15 letters. Packages that don’t fit go into a parcel locker or are held at the counter, so the smallest box can still work if you get only occasional packages.
Are there one-time fees when you rent a USPS PO Box?
Usually just a refundable key deposit for each of the two keys USPS issues, and some new customers at competitive locations pay no deposit for those keys. Extra keys add a refundable deposit and a non-refundable fee, and changing a lock carries its own fee. Deposits are returned when you hand back the keys.
Who qualifies for a free USPS PO Box?
Under USPS Group E rules, you may qualify for a free PO Box if your physical address is within the Post Office’s delivery ZIP Code and could receive carrier delivery, but USPS doesn’t deliver to a mailbox at or near it. It’s limited to one free box per delivery point, and you must apply in person.
Is a PO Box cheaper for 12 months than 6 months?
A 12-month term means one payment and fewer chances of missing a renewal. New customers at competitive locations also get 13 months of service for a 12-month payment. Compare the 6-month and 12-month fees for your specific box on the USPS PO Boxes page before you choose.
Sources
- USPS: PO Boxes (find a box, sizes, payment periods, Premium PO Box Service)
- USPS: PO Box sizes
- USPS Domestic Mail Manual 508.4: Post Office Box Service
Part of our USPS Locations guide. Related: USPS Shipping Guide, USPS Collection Box.
