Is there a difference between physical address and mailing address?

Yes. A physical address is where the business is located, and forms often call it a street address or principal office address. A mailing address is where mail for the business should be sent. On Form SS-4, the mailing address line allows a P.O. Box and the street address line says not to enter one.

Can a business mailing address be a P.O. Box?

On IRS Form SS-4, yes. The label for line 4a includes “or P.O. box.” The street address line on Form SS-4 and the principal office street address on California’s LLC-1 both say not to enter a P.O. Box. Check the label on each form, because each form sets its own rule.

What address does a bank need for a business account?

Under the federal customer identification rule, 31 CFR 1020.220, a bank must get “a principal place of business, local office, or other physical location” for a business customer. The rule sets a minimum, so a bank can ask for more, such as a separate mailing address.

What is a physical address for a business?

It is the street location where the business operates. The IRS instructions for Form SS-4 call the street address line the entity’s physical address and say not to enter a P.O. box number there.

Mailing Address vs Physical Address for Business: Where Each Goes

Q: Can a business address and a mailing address be different?

Yes. Some forms ask for a second address only if it is different. IRS Form SS-4 asks for the street address only if it is different from the mailing address. California’s LLC-1 asks for the mailing address only if it is different from the principal office street address.

Short answer

A mailing address is where your business gets its mail. On some forms it can be a P.O. Box, such as line 4a of IRS Form SS-4. A physical address is the street location of the business. Line 5a of Form SS-4 and the principal office line on California’s LLC-1 both say not to enter a P.O. Box. The two addresses can be different.

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Key takeaways

A mailing address is where mail for the business should be sent. A physical address is where the business is located. Forms often call the second one a “street address” or a “principal office” address.
On IRS Form SS-4, line 4a is the mailing address and its label includes “or P.O. box.” Line 5a is the “Street address (if different)” and says “Don’t enter a P.O. box.”
California’s LLC-1 asks for the “Initial Street Address of Principal Office - Do not enter a P.O. Box” and, separately, the “Initial Mailing Address of LLC, if different than item 2a.”
Florida law says LLC articles of organization must state “The street and mailing addresses of the company’s principal office.”
The federal bank rule for customer identification asks a business for “a principal place of business, local office, or other physical location.” It does not list a mailing address as a choice.

What is the difference between a mailing address and a physical address?

A mailing address is the address where mail for your business should be sent. A physical address is the place where your business is actually located. The two can be different, for example when the owner works from home but gets mail at a P.O. Box.

The forms in this guide do not use the words “physical address” in the field name. They use other words for the same idea. The IRS Form SS-4 calls it a “Street address.” State LLC forms often call it the “principal office” address. In its instructions for line 5a of Form SS-4, the IRS says to provide “the entity’s physical address,” so the IRS treats the street address line as the physical address.

On Form SS-4, the mailing address line is the more flexible one. The label for line 4a reads “Mailing address (room, apt., suite no. and street, or P.O. box).” The street address line next to it reads “Street address (if different) (Don’t enter a P.O. box.)” So on this form a P.O. Box can go on the mailing line and cannot go on the street line.

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Can a business address and a mailing address be different?

Yes. The forms we read expect that some businesses will have two addresses. IRS Form SS-4 and California’s LLC-1 ask for the second address only when it is different. Florida’s statute asks for both the street and mailing addresses of the principal office.

On Form SS-4, the IRS instructions for lines 5a and 5b say to provide the physical address “only if different from its mailing address.” If the two are the same, you fill in the mailing address on lines 4a and 4b and leave the street address lines blank.

California’s Articles of Organization for an LLC, form LLC-1, works the same way. Item 2a is the “Initial Street Address of Principal Office - Do not enter a P.O. Box.” Item 2b is the “Initial Mailing Address of LLC, if different than item 2a.” The words “if different” mean you only fill in item 2b when mail should go somewhere other than the principal office.

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Which forms ask for a mailing address and which ask for a physical address

The table below shows the exact field names on four common filings. The words in quotation marks come from each form, statute, or regulation. Read the field name in full before you fill it in, because the note at the end of the label is often the rule.

Filing	Mailing address field	Street or physical address field
IRS Form SS-4 (Rev. December 2025), EIN application	Line 4a: “Mailing address (room, apt., suite no. and street, or P.O. box)”	Line 5a: “Street address (if different) (Don’t enter a P.O. box.)”
California Articles of Organization, form LLC-1	Item 2b: “Initial Mailing Address of LLC, if different than item 2a”	Item 2a: “Initial Street Address of Principal Office - Do not enter a P.O. Box”
Florida Articles of Organization, form CR2E047	“Mailing Address” under Article II	“Principal Office Address” under Article II. Florida Statutes section 605.0201 calls it the street address of the principal office.
Bank account opening, 31 CFR 1020.220	The rule does not list a mailing address as a choice.	For a business: “a principal place of business, local office, or other physical location”

From IRS Form SS-4 and its instructions, California form LLC-1, Florida form CR2E047 and Florida Statutes section 605.0201, and 31 CFR 1020.220, read on October 31, 2026.

How the IRS uses each address on Form SS-4

The IRS uses the two SS-4 addresses for different jobs. For lines 4a and 4b, the instructions say “Enter the mailing address for the entity’s correspondence.” They add: “Generally, this address will be used on all tax returns.” So the mailing address is where IRS letters about your EIN and your returns are sent.

The street address on lines 5a and 5b tells the IRS where the business is. The instructions say “Don’t enter a P.O. box number here.” Line 6 then asks for the county and state where the principal business is located. For that line the instructions say “Enter the entity’s primary physical location.”

If your mailing address changes later, the instructions say “File Form 8822-B to report any subsequent changes to the entity’s mailing address.” Our guide to the address to use on Form SS-4 covers the registered agent and foreign address questions on this form.

What state LLC filings ask for

California and Florida LLC filings both ask for a principal office address and a mailing address. They show two ways to write the same request.

In Florida, the statute sets the rule. Section 605.0201 of the Florida Statutes says the articles of organization must state “The street and mailing addresses of the company’s principal office.” The Division of Corporations form for Articles of Organization, CR2E047, asks for both side by side under Article II, with one box labeled “Principal Office Address” and one labeled “Mailing Address.” The same form prints “P.O. Box NOT acceptable” under the registered agent’s Florida street address. Our guide to the Sunbiz principal address and mailing address explains both Florida fields in more detail.

In California, the rule is printed on the form itself. Item 2a of form LLC-1 asks for the street address of the principal office and says “Do not enter a P.O. Box.” Item 2b asks for the mailing address only if it is different. The registered agent is a third address on both forms. Our guide to the three business addresses every LLC needs explains where the agent’s address fits.

What a bank asks for when you open a business account

Banks follow a federal rule that requires a Customer Identification Program. For banks it is 31 CFR 1020.220. The rule says a bank “must obtain, at a minimum, the following information from the customer prior to opening an account.” Address is one of the items.

The rule lists the address a bank must collect for each type of customer. For an individual, it is “a residential or business street address.” For a customer that is not an individual, “such as a corporation, partnership, or trust,” it is “a principal place of business, local office, or other physical location.” The rule does not list a mailing address or a P.O. Box as one of the choices for a business.

The Financial Crimes Enforcement Network (FinCEN) and the federal bank regulators issued a joint list of questions and answers about this rule, back when it was numbered 31 CFR 103.121. In an answer about customers in rural areas who have no residential or business street address, they said: “A rural route number, unlike a post office box number, is a description of the approximate area where the customer can be located.” That answer is about individual customers, not businesses, but it shows how the agencies read the address item in this rule: as a description of where the customer can be located.

The words “at a minimum” mean a bank can ask for more than the rule lists. Your bank’s own application may also ask for a mailing address. The rule we read does not say whether a virtual office or a mailbox service address counts as a physical location. Ask the bank before you apply.

How to decide which address goes on which line

Start with the field name. If the label says “street address,” “physical location,” or “principal office,” or says not to enter a P.O. Box, the form wants the place where the business is located. If the label says “mailing address,” the form wants the place where your mail should go, and some forms allow a P.O. Box there.

Next, check whether the form says “if different.” If it does, and your business gets mail at the same place it operates, you can leave the second line blank. If you are not sure whether your LLC needs a street address at all, our guide to whether an LLC needs a physical address goes through the formation forms one state at a time.

None of the forms we read say whether a virtual office or a mailbox service address meets the street address or physical location test. Where the form says “street address” or “physical location,” quote that wording to the agency or the bank and ask them. Before you list any address, our free address checker shows how USPS classifies it.

If you are looking for a place to receive general business mail, our Silicon Valley virtual office address and Los Angeles business address pages describe the business addresses save office offers.

Not legal or tax advice

This guide summarizes IRS Form SS-4 and its instructions, California form LLC-1, Florida form CR2E047 and Florida Statutes section 605.0201, and 31 CFR 1020.220, as read on October 31, 2026. Forms and rules can change. Check the current form before you file, and ask the agency, your bank, or a professional about your own situation.