How to Port an Existing Fax Number to an Online Fax Service

Disclosure: Fax Ledger earns affiliate commissions from CJ partners including MetroFax and RingCentral Fax at no extra cost to you. All information about porting processes is based on published vendor documentation and general carrier porting standards; specific timelines and requirements vary by vendor and carrier.

Your fax number is on your business cards. It is listed on the state medical association directory, the state bar's attorney search, the MLS roster, your insurance provider panels, or your supplier contracts. Changing that number means updating every one of those listings — a significant administrative effort that many businesses simply cannot absorb without disrupting operations.

The good news: you do not have to change your fax number to switch from a traditional fax machine or a previous online fax service. Most online fax services support number porting — the process of transferring your existing fax number to a new service — so you keep the number while shedding the physical fax machine, dedicated phone line, or prior subscription.

This guide covers how fax number porting works, what documentation is typically required, what to expect for timelines and fees, and what MetroFax and RingCentral Fax publish about their porting processes.

What Is Fax Number Porting?

Fax number porting is the telecommunications industry process of transferring a phone number — in this case, your fax number — from one carrier or service (the "losing" carrier) to another (the "gaining" carrier). The process is governed by FCC regulations that require carriers to release a number at the customer's request, provided the account is in good standing and the proper documentation is submitted.

For practical purposes: your existing fax number does not belong to your fax machine or your current fax service. It is assigned by a telecommunications carrier. Porting transfers that assignment to a new carrier (your new online fax service's underlying carrier).

When Porting Makes Sense

Fax number porting is worth the effort when:

• Your fax number appears in professional directories, referral networks, or published listings
• Your number is printed on business cards, letterhead, or signage
• Patients, clients, or customers have your fax number saved in their own systems
• You have a toll-free fax number that your business actively markets

Porting is less critical if you are setting up a new fax number for the first time, or if your existing fax number is known only to a small number of contacts who can easily be notified of a change.

Step-by-Step: How to Port Your Fax Number

Step 1: Choose Your New Online Fax Service and Subscribe

Before initiating a port, you need an active account at your destination service. You cannot port to a service you have not subscribed to.

MetroFax and RingCentral Fax both publish number porting as a supported feature. Subscribe to the plan that matches your page volume before beginning the porting request.

Affiliate disclosure: Fax Ledger may earn a commission if you subscribe through our links.

Start with MetroFax → | Start with RingCentral Fax →

Step 2: Gather Your Current Carrier Documentation

Most porting requests require documentation from your existing carrier or fax service:

Incomplete or mismatched documentation is the most common cause of porting delays. Double-check that the name, address, and account number on the LOA match the information on your current carrier account exactly.

Step 3: Submit the Porting Request

Submit the porting request to your new online fax service. Most services have a porting request form or a support ticket process. You will provide:

• The fax number to be ported
• Your account information at the new service
• The documentation gathered in Step 2

At MetroFax, porting requests are handled through customer support. At RingCentral, porting for fax numbers follows RingCentral's published number porting process for business accounts.

Step 4: Do NOT Cancel Your Existing Fax Service

This is the most important step that people get wrong. Do not cancel your current fax service or phone line until the port is complete. If you cancel the losing carrier account before the port completes, the number may be released and become unportable. Incoming faxes during the porting window will continue to arrive at your current service until the port goes live.

Step 5: Await Confirmation of Port Completion

Published porting timelines from major fax service vendors are typically 10–14 business days from the time a complete, accurate request is received. Timeline factors include:

• Whether the losing carrier processes port requests quickly
• Whether documentation is complete on the first submission
• Whether the number type (local vs toll-free) affects the processing channel

Your new fax service should notify you when the port is complete. Do a test by having someone fax a document to your number and confirm it arrives at your new service.

Step 6: Cancel Your Old Fax Service

Only after confirming the port is complete and your number is receiving faxes at the new service should you cancel your previous fax subscription or phone line.

Porting Timelines by Number Type

Porting Fees: What Published Information Shows

Some online fax services do not charge a porting fee; others charge a one-time fee of $10–$20. This information is often found in the fine print of the pricing page or in the porting request documentation. Ask explicitly about porting fees before submitting a request.

Common Porting Problems and How to Avoid Them

What MetroFax and RingCentral Fax Publish on Porting

MetroFax publishes number porting as a supported feature on its plan documentation. The porting request is handled through customer support. For a small business or solo professional that wants a straightforward value plan with a high page allowance ($12.95/month, 500 pages), MetroFax is a solid landing point for a ported number.

RingCentral Fax supports number porting as part of its broader UCaaS platform's number management. The process follows RingCentral's standard business number porting workflow, which is documented publicly. For a team already on RingCentral's phone platform, porting a fax number into the same ecosystem simplifies administration.

Bottom Line

Fax number porting allows you to take your existing fax number to an online fax service and eliminate the hardware, consumables, and dedicated phone line costs of a traditional fax setup — without losing the published number that patients, clients, or business partners already have on file.

The key to a smooth port: gather your documentation carefully, do not cancel your old service prematurely, and allow the full published timeline (10–14 business days) for the transfer to complete.

Port to MetroFax → | Port to RingCentral Fax →