How to Find Out the Phone Number of a Line

By Matt McGew

If you don't know the phone number of a particular phone line, you can find out the phone number associated with that phone line by calling special toll-free phone number from your phone line. Alternatively, you can also call your local phone company or call another phone that subscribes to a caller ID service from your phone line. You can use any of these methods to find out the phone number of a specific phone line.

Step 1

Lift the handset of the phone connected to the line you want to find the phone number for. Wait until you hear the dial tone. Dial 800-444-0800, 800-444-2222, 800-444-3333, 800-444-4444 or 800-444-5555 using the keypad on your phone. Wait for the automated message to play a short message that includes the number associated with the phone line you called from.

Step 2

Call the customer service phone number for your local phone company from the phone line you want to find out the phone number for. You can find out the phone number for your local phone company by looking at your monthly bill or dialing "411" from your phone line. Verify your identity. After you call the customer service phone number for your local phone company, the customer service representative will ask you a series of questions to verify your identity. These questions may include your name, Social Security Number or billing address. Ask the customer service representative for the phone number associated with the phone line you are calling from. The customer service representative will give you the phone number.

Step 3

Call a phone that subscribes to caller ID service from the phone line you want to find out the phone number for. Look at the caller ID display or ask another person to look at the caller id display of the line you called. The number that appears on the caller ID display is the phone number of the line you are calling from. If the phone number of the line does not appear on the caller ID display, dial "*82" prior to dialing the phone number that subscribes to the caller ID service to unblock your phone line's caller ID information.