Five box sizes
The fee goes up with the size of the box. Size 1 is the smallest. Size 5 is the largest.
The fee group
Each post office's 5-digit ZIP Code sits in a fee group. The same size can cost more in one place than another.
3, 6, or 12 months
You pay for a term up front. The 3-month term renews on its own.
Why USPS does not print one PO Box price
The USPS PO Box page, read October 20, 2026, says pricing differs depending on your location. It sends you to the PO Box finder to see local rates. It does not print a national price.
The rule behind that is in section 508.4.4.1 of the Domestic Mail Manual. Box fees are based on the box size and the fee group of the 5-digit ZIP Code. The manual also splits post offices into two kinds. Section 508.4.5.1 calls some locations competitive and others market dominant. That label changes the extras you get, covered below.
The dollar tables sit in a USPS price list called Notice 123. We could not read the PO Box table on the copy we opened, so this page does not repeat a fee. When you look up a box, write down the size, the term, and the total. That total is the number to compare.
The 2026 price change
PO Box prices move with the Postal Service's price changes. A Federal Register notice published November 19, 2025 reprints Governors' Decision No. 25-6. It says competitive Post Office Box prices would increase 5.7 percent on average, within the existing price ranges. The changes took effect January 18, 2026. The notice points to the Mail Classification Schedule for the new prices.
That 5.7 percent is an average for competitive locations. It is not the change at your post office. Look up your own location for the current number.
Box sizes
The USPS page says most locations offer five sizes, subject to availability. Most boxes are 14.75 inches deep.
| Size | Opening | What USPS says it holds |
|---|---|---|
| XS (size 1) | 3 x 5.5 inches | 10 to 15 letters, or 3 rolled magazines. |
| S (size 2) | 5 x 5.5 inches | 15 or more letters, 5 rolled magazines, or 1 small Priority Mail Flat Rate Box. |
| M (size 3) | 5.5 x 11 inches | Large envelopes and magazines, plus 2 small Flat Rate Boxes. |
| L (size 4) | 11 x 11 inches | Small and medium Flat Rate Boxes, plus 10 to 15 letters. |
| XL (size 5) | 12 x 22.5 inches | Multiple packages. |
Start small if you mostly get letters. A package that does not fit is held at the counter or put in a parcel locker, so a small box does not lose packages. It only means more trips to the counter.
Do not start too small if you get a lot of mail. Section 508.4.3.3 says that if your mail does not fit on 12 of any 20 business days in a row, the post office can make you move to a bigger box, add boxes, or use caller service. Caller service is a separate paid service for very large volumes.
Terms, renewals, and refunds
The USPS page lists terms of 3, 6, or 12 months. The 3-month term needs automatic renewal, with no opt-out. The 6-month and 12-month terms let you opt out. The manual, at 508.4.1.7, describes the 12-month term as two 6-month periods paid in advance.
When the term starts matters. Section 508.4.4.4 says the period starts on the first day of the month if your box is approved on or before the 15th. After the 15th, it starts the next month.
Renewal is due in the last 30 days of the term, and no later than the last day. The USPS page says payments are due by the 10th of the month and a box closes on the 11th if it is not paid. Section 508.4.7.5 adds a late charge: if you renew more than 10 days after the due date, you pay the lock replacement fee.
Refunds are limited. Section 508.4.6.1 says that if you close a box within the first 3 months of a 6-month period, you get half the fee back. After the start of month four, you get nothing back for that period. If you prepaid the next period, that whole period is refunded. A 3-month term on automatic renewal gets no refund.
Keys and other fees on top of the box
You get two keys, or a combination, after you pay and the clerk checks your two IDs. Section 508.4.7.1 says each key carries a refundable deposit. At competitive locations in fee groups 30 to 44, the first two keys have no deposit. You get a deposit back when you return the key.
Extra keys cost more. Section 508.4.7.2 says you apply on PS Form 1094 and pay a deposit plus a fee you do not get back. A worn or broken key is replaced free when you return it. A new lock is a separate fee you do not get back.
Competitive locations add a few extras. Section 508.4.5.4 lists 13 months of service for the price of 12 for new customers, Street Addressing, and an optional Signature on File. Street Addressing lets you use the post office street with # and your box number, so UPS, FedEx, and Amazon packages can reach the box. That option is covered in PO Box vs virtual mailbox.
When a PO Box is free
Some people pay nothing. Section 508.4.5.2 describes fee group E. You may qualify when your address is inside that post office's delivery area, the address could get carrier delivery, and the Postal Service does not deliver there. That is one free box per delivery point. Section 508.4.5.3 rules out some places, such as hotels and gated communities. Ask at the counter if you have no mail carrier.
How a PO Box cost compares with a private mailbox
A private mailbox is a box at a business, not a post office. It is a commercial mail receiving agency (CMRA). A CMRA is a private business the Postal Service lets receive mail for other people. USPS Form 1583 is the USPS form that authorizes a CMRA to accept your mail. A PO Box uses a different form, PS Form 1093.
The UPS Store is one kind of private mailbox. Its personal mailbox page, read October 20, 2026, says prices may vary because each location is individually owned and operated. It does not print one price either. The same page says the mailbox takes packages from all carriers and gives you a street address with PMB or # and your box number.
A virtual mailbox is a private mailbox that scans the outside of each envelope and shows it to you online. The plan is the rent for the street. Scans, postage, and check deposits can cost extra. What a virtual mailbox costs lists what each company's own page printed. City pages show the local version. Boston, Detroit, Memphis, and Raleigh each name the stores and the prices those stores or apps printed. Compare a full year, not one month.
Price is not the only test. A PO Box and a private mailbox both fail the bank field that asks where a business operates. KYC means Know Your Customer: the checks a bank uses to confirm who you are. Google Business Profile is the listing Google uses for Maps and search, and Google's guidelines say P.O. boxes are not acceptable. A cheaper box does not fix either one.
How to get the lowest PO Box price
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Pick the smallest size that fits
Most letter-only households do fine with size 1 or 2. Packages wait at the counter or in a locker either way.
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Check more than one post office
The fee group follows the ZIP Code. Look up two or three nearby locations in the finder before you pick.
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Compare the 12-month total
At a competitive location, a new customer gets 13 months for the 12-month price. A 3-month term renews on its own and has no refund.
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Renew on time
Pay before the 10th. A box unpaid on the 11th closes, and a late renewal adds the lock replacement fee.
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Keep your keys
Return them when you close the box. The deposit comes back. A lost key means a new key fee, and maybe a new lock.
Questions people ask first
How much is a PO Box per month?
USPS sells terms of 3, 6, or 12 months, not month by month. Divide the term price by the months to get a monthly figure. The term price depends on size and ZIP Code.
Why is my post office more expensive than my friend's?
The fee is set by the fee group of each post office's ZIP Code. Two post offices can sit in different groups.
Do I get money back if I close my PO Box early?
Sometimes. Closing within the first 3 months of a 6-month period returns half. After that, nothing for that period. Key deposits come back when you return the keys.
Is a PO Box cheaper than a virtual mailbox?
Often, but compare full-year totals. A virtual mailbox charges a plan plus extras for scans and postage. A PO Box has no scan, so you pay with trips to the counter instead.
Can I get a PO Box for free?
Only if the Postal Service does not deliver to your address and it sits in that post office's delivery area. That is fee group E.
Sources
- USPS, PO Boxes. Read October 20, 2026. Pricing differs by location and the PO Box finder shows local rates. Terms of 3, 6, or 12 months. Five sizes and their contents. Payment due by the 10th, and a box closes on the 11th if unpaid.
- USPS Domestic Mail Manual 508.4. Read October 20, 2026. Fees by box size and ZIP Code fee group. Competitive and market dominant locations. Start dates, renewal, refunds, key deposits, key and lock fees, the late charge, the overflow rule, free fee group E boxes, and the competitive extras.
- Federal Register, November 19, 2025, Governors' Decision No. 25-6. Read October 20, 2026. Competitive Post Office Box prices up 5.7 percent on average, effective January 18, 2026.
- The UPS Store, personal mailboxes. Read October 20, 2026. Prices may vary because locations are individually owned. PMB or # address. Packages from all carriers. Two IDs and PS Form 1583.
- Google, guidelines for representing your business. Read October 20, 2026. P.O. boxes are not acceptable.