The short answer
A USPS PO Box costs $21–$98 for three months or $31–$170 for six months for the smallest box (Size 1), under USPS’s current Notice 123 price list (October 4, 2026). The price depends on the box size and the fee group of the Post Office’s ZIP Code. A year is two 6-month periods, so $62–$340. Larger boxes cost more, up to $677 for six months, and USPS’s PO Box lookup shows the exact price at any Post Office.
How much is a PO Box at the post office?
USPS sets PO Box fees in Notice 123, its official price list, and the fee for any one box depends on two things: the box size and the fee group assigned to the Post Office’s 5-digit ZIP Code. The Domestic Mail Manual says exactly that in section 508.4.4.1. That’s why two people asking “how much is a PO Box” can get answers that differ by more than $100.
Under USPS’s current Notice 123 price list, the smallest box (Size 1) costs $31–$170 for six months, depending on location. The cheapest fee group charges $21 for three months, and the most expensive charges $98. Bigger boxes cost more at every location; the largest Size 5 box runs $156–$677 for six months.
You pay in advance for the whole term. USPS doesn’t bill PO Boxes monthly, so a “monthly” price is just the term fee divided by the number of months.
Why do PO Box prices vary by location?
Every Post Office with boxes is placed in a fee group. Notice 123 lists market-dominant fee groups 1–7 and competitive fee groups C30–C44. DMM 508.4.1.2 explains the split: competitive PO Box service is offered where a competing mailbox provider serves the area, and market-dominant service is offered where no nearby competitor does.
Competitive locations generally cost more but can offer extras such as Street Addressing (covered below). Notice 123 doesn’t list ZIP Codes. Instead, it sends you to usps.com/manage/po-boxes.htm or your local Post Office to find the fee group for a ZIP Code. In practice, the easiest way to see your exact price is to search a ZIP Code or address under “Find a PO Box Near You” on that page, which shows the sizes, terms, and prices for nearby Post Offices.
USPS can also change the fee group for a ZIP Code, not just the prices, so check the lookup before renewing rather than assuming last year’s fee.
What are the PO Box prices by size?
The table below shows the six-month fee for each box size, from the cheapest fee group to the most expensive, in each of the two pricing categories. Your Post Office charges one exact figure within these ranges.
| Box size | Market-dominant groups 1–7 | Competitive groups C30–C44 |
|---|---|---|
| Size 1 (XS) | $31–$81 | $80–$170 |
| Size 2 (S) | $41–$118 | $103–$225 |
| Size 3 (M) | $60–$206 | $161–$395 |
| Size 4 (L) | $90–$355 | $193–$452 |
| Size 5 (XL) | $156–$553 | $270–$677 |
How much is a PO Box for 3 months, 6 months, or a year?
USPS offers three payment terms: 3, 6, or 12 months. Under DMM 508.4.4.3, a 12-month term is two prepaid 6-month periods, so a year costs twice the 6-month fee. Notice 123 lists a separate quarterly fee, and it is a little more than half the 6-month fee. For the smallest box, it works out like this:
- A 3-month term requires automatic renewal, and USPS says you can’t opt out of it. With a 6- or 12-month term, you can opt out.
- Renewals can be paid during the last 30 days of a term. USPS says payment is due by the 10th of the month it’s due, and a box that isn’t paid is closed on the 11th.
- If you close a box within the first three months of a 6-month period, DMM 508.4.6 refunds half the fee; after that, none. A prepaid next period is refunded in full.
| Term | Lowest fee group (market-dominant 7) | Highest fee group (competitive C30) |
|---|---|---|
| 3 months | $21 | $98 |
| 6 months | $31 | $170 |
| 12 months (two 6-month periods) | $62 | $340 |
| Monthly equivalent of a 12-month term | About $5.17 | About $28.33 |
What size PO Box do I need?
Most Post Offices offer five sizes, but not every location has every size. USPS gives these front dimensions and says most boxes are 14.75 inches deep. If your mail outgrows your box, DMM 508.4.1.3 lets the postmaster require a larger one.
| Size | Front opening | What USPS says fits |
|---|---|---|
| 1 (XS) | 3 × 5.5 in. | 10–15 letters and 3 rolled magazines |
| 2 (S) | 5 × 5.5 in. | 15+ letters, 5 rolled magazines, or 1 Small Priority Mail Flat Rate Box |
| 3 (M) | 5.5 × 11 in. | Stacked large envelopes and magazines, or 2 Small Flat Rate Boxes |
| 4 (L) | 11 × 11 in. | Small and Medium Flat Rate Boxes plus 10–15 letters |
| 5 (XL) | 12 × 22.5 in. | Multiple packages |
How do I get a PO Box?
You can start online or at the counter. Either way, you finish in person at the Post Office where the box is located, because that’s where USPS checks your ID and gives you two keys or the lock combination.
- Online: search a ZIP Code or address on usps.com/manage/po-boxes.htm, pick a Post Office, box size, and term, then complete the application and pay by card to reserve the box. Print the form it generates and bring it to the box’s Post Office, with your ID, within 30 days.
- In person: download and fill out PS Form 1093, Application for Post Office Box Service, or get one at the counter. Bring it with your payment and ID and ask for a PO Box.
- ID: everyone listed on the application except minors must show two current IDs. PS Form 1093 says one must have a photo, such as a driver’s license, state ID, or passport, and the other must be traceable to you and prove your physical address.
- No box available? USPS lets you pick another size or location, or join a wait list. When a box opens, you get 2 days to reserve it.
Are there other PO Box fees, like keys or locks?
A few. Two keys are issued when you open the box. Notice 123 lists a refundable $6 deposit per key, but there’s no deposit on the first two keys at competitive locations. Extra keys need PS Form 1094 and cost $14 each, plus the deposit. The deposit is refunded for each key you return when you close the box.
The lock replacement or late payment fee is $30. These figures are the same in market-dominant and competitive fee groups.
Can you get a free PO Box?
Yes, if USPS won’t deliver to your home. DMM 508.4.5.2 describes Fee Group E, a free PO Box. It’s for an address that is within a Post Office’s delivery ZIP Code boundaries and could be a carrier delivery point, but gets no carrier delivery to a mailbox at or near the address. Only one free box is allowed per delivery point, and it’s the smallest available box that reasonably holds your daily mail.
Group E doesn’t cover everyone without door delivery. DMM 508.4.5.3 excludes people who get, or could get, single-point delivery at places like hotels, colleges, or military installations. It also excludes addresses served by cluster boxes or mailrooms, and locations where carriers can’t deliver because of things like private roads, gated communities, or local ordinances. PS Form 1093 notes that you can’t apply online for a free box, so ask at your Post Office.
Can a PO Box receive packages from UPS, FedEx, or Amazon?
Only with Street Addressing. At competitive locations, DMM 508.4.5.4 lets box customers sign a customer agreement to use the Post Office’s street address with their box number after a # sign, as in “John Smith, 123 Main Street #4567, Any Town, NY 10001.” With that address, private carriers can deliver packages to your box if they meet USPS mailability rules, including a 70-pound maximum and 130 inches in length plus girth. USPS lists Amazon, DHL, FedEx, and UPS as examples and notes that availability varies.
USPS packages that don’t fit go to the counter, and a slip is left in your box. Or you pick them up from a parcel locker at some locations. For items that need a signature, free Signature on File lets USPS leave the item in your box instead. Our PO Box address guide covers how to write both address formats correctly.
What’s the difference between a PO Box and a private mailbox?
A PO Box is rented from USPS at a Post Office. A private mailbox (PMB) is rented from a commercial mail receiving agency (CMRA), which DMM 508.1.8 defines as a private business that accepts mail for other people as a service. Mail stores fall in this category. The CMRA receives the mail and holds it for pickup or remails it with new postage.
The paperwork differs. A PMB customer completes PS Form 1583, Application for Delivery of Mail Through Agent, and shows primary and secondary ID. Each spouse needs a separate form. Mail to a PMB uses “PMB” or “#” with the box number, not “PO Box.” CMRA fees are set by each business, not by USPS, so compare the quoted price, the address format, and the package-receiving terms against a PO Box’s Notice 123 fee.
Can I mail a letter to a PO Box online?
IRIS Postal Forms is an independent print-and-mail service, not USPS. It doesn’t rent PO Boxes or receive mail for you. But a PO Box is a US address, so IRIS can mail a letter there. You upload a US Letter-size PDF and enter the sender and the PO Box address. Then you review the document, addresses, options, and total before paying. IRIS prints it and sends it by USPS First-Class Mail. You don’t need stamps or an envelope.
A one-page black-and-white letter is $3.20. Certified Mail adds $6.95, for letters up to six sheets, with tracking on your order page. If the recipient’s address is a PO Box, read our guide to Certified Mail to a PO Box first.
Sources & further reading
Product details checked against the IRIS API contract when this article was published. Platform references can change; consult the linked documentation when implementing.
- USPS Notice 123: Price List
- USPS Domestic Mail Manual 508: Recipient Services
- USPS: Rent a PO Box
- USPS PS Form 1093, Application for Post Office Box Service (PDF)
Published by IRIS Postal Forms, operated by Great Lakes Computing Office LLC. Send a correction.