How to Find a Fax Number

Co-authored by Mitch Harris

Last Updated: October 6, 2022

A fax machine sends documents electronically using a phone line. To find a fax number for a particular business, go to the business' website or call the business directly. If you need to find your own fax number, try calling a personal cell phone from your fax machine and look at the caller ID for the number. If you already have the fax number but need to determine who sent you the fax, do a "reverse lookup" search online by typing the fax number into a search engine or directory. With any option, you can easily locate a fax number.

Method 1

Method 1 of 3:

Determining Your Own Fax Number

1
Call 1-800-444-4444 for an easy way to find out your fax number. Your fax number is connected to a phone line, and the number associated with the phone line is your fax number.^{[1]
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Research source} From the landline associated with the fax machine, call 1-800-444-4444, a toll-free line operated by MCI (a telecommunications company). An automatic operating system will recall your fax number for you. ^{[2]
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- This is an easy and straightforward way to determine your fax line.
- The operator gives you your number automatically. You don't need to provide any additional information.
2
Use the fax machine to call a phone with caller ID if that's easier for you. Another way to find out your fax line is to use the fax machine itself. Using a landline or smartphone with caller ID, call the phone with your fax number and check the caller ID on your phone to see what number comes up.^{[3]
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Research source} The number displayed after the phone connects is your fax number.^{[4]
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- For example, if you don’t know the number of your work fax machine, call your personal cell phone with the machine. Then, write down the fax number as listed on your phone.
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3
Log into your account if you have an online fax provider. An online fax service is a third-party company that charges a small fee to use a personalized fax line, online services included efax.com or jfax.com and enroll. Type in your username and password to log in and go into your account settings. Then, click your account settings tab and find the fax number listed on this page.^{[5]
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Method 2

Method 2 of 3:

Locating Business Fax Numbers

1
Check the business’ website to see if their fax number is listed. Go to the website of the company that you want to fax, and look for the “Contact Us” section. Click on this to see what contact options are available. While not all companies do this, many businesses and organizations will list their fax number directly, along with phone numbers and email addresses.^{[6]
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- If you are unsure of what the business’ website is, type the business name in an Internet search engine.
2
Search the Internet to locate the fax number if it's not on their website. Use a search engine of your choice and type in the business name. Add “fax number” after the business name to specify your search and press “enter.” Then, skim through the search results to see if their fax number is listed on another website.^{[7]
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- For example, you may find the business’ “Contact Us” page listing their fax number.
- You can also use phone directory websites to find fax numbers. These are particular sites that have a directory of fax numbers across many different types of businesses.
3
Contact the business to ask them directly if the fax number is not online. While most companies have a “Contact Us” section, they may only list a phone number or email address. Dial the contact number listed and ask an associate for the fax number. If there is no phone number listed, try emailing instead.^{[8]
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- Calling is a more direct way to get the fax number, as there is no guarantee your email will be answered.

Method 3

Method 3 of 3:

Tracing a Fax Number Back to the Source

1
Locate the number that the fax was sent from. On the printed page, look across the top or bottom of the page for a 10-digit phone number. In addition, look at the display screen on the fax machine and select “recent faxes.” Scroll through the most recent faxes to find the number you want to trace.^{[9]
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- When you do this, try to get the area code as well. This helps you narrow down your options as you search for the correct line.
2
Find a telephone directory site to do a reverse phone number search. Online telephone directories offer information much like a phone book, but they often have a much wider range of information. Search online for “telephone directory” and browse your options. Make your decision based on which directories offer reverse phone number searches.^{[10]
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- A reverse number search is where you use a phone number to locate the name of a business or individual, rather than searching with the name in order to find the number.
3
Enter the fax number into the directory site. When you go to the directory’s website, look for the “Reverse Phone” tab. Click the tab, type your fax number into the search bar, and then press “enter.” The window that pops up lists any relevant information tied to that phone number, such as a name and address.^{[11]
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- If the fax number is tied to a business, the company name and address is usually listed.
- If the fax number is tied to a personal fax machine, you may receive information either on the owner or from the phone line carrier provider.

Community Q&A

Question

How can I find out my own home fax number if I forgot it?

Community Answer

Make a phone call from the number to a phone that has caller ID or call the phone company and ask them for the phone numbers associated with your account.
Question

How do I find my fax number?

Community Answer

Your fax number is the same telephone number that you connected the fax machine to. If you only have one number, it's the same as the voice number. If it is a separate line, then use the fax to call someone that has caller ID, and they can tell you the number the fax is dialing from.
Question

Is my landline phone number the same as my fax number?

Community Answer

Not always, but it could be. If you only have one telephone line, then your landline number could also be your fax number.