If you want switch to an Internet fax service without changing your fax number, you'll need to "port" that fax number — that is, move the number from its current service (the phone company or service that owns it) to its new service (the new service that will own the number.) This can be tricky. Not all services will let you port out (that is, give up the number to a competitor.) Some that do will charge you a fee. On the other hand, not all services will let you port a number in (that is, move a number to them.) Here's my chart of which fax services let you port numbers around.
| Fax Service | Port In? | Port Out? | Fee | Notes |
|---|---|---|---|---|
| FaxItNice | NO | NO | N/A | |
| Fax1 | YES | YES | none | |
| MaxEmail | YES | NO | none | If you ported a number in, MaxEmail must allow it to be ported out, per FCC rules. |
| SRFax | YES | YES | $25/port in none/port out |
Toll free numbers can be ported; ability to port local numbers varies. |
| FlatRateFax | YES | SOMETIMES | $10 | Porting out is allowed only if you ported the number in. No fee. |
| eFax | YES | SOMETIMES | $40/port in unknown fee/port out |
If you ported a number in, you can port it out for $40. If local law requires, you can port out an eFax-provided number for a fee |
| RapidFAX | YES | SOMETIMES | $40/port in up to $100/port out |
If you ported a number in, you can port it out for $40. If local law requires, you can port out a RapidFax-provided number for a fee of up to $100. |
| FaxAge | YES | SOMETIMES | $20 | Porting out is allowed if you ported the number in. No fee. Site has tool to check if number is portable. |
| Fax.com | YES | NO | $40/port in unknown fee/port out |
If you ported a number in, you can port it out for $40. If local law requires, you can port out an Fax.com-provided number for a fee. |
| SmartFax | YES | NO | $40/port in $40/port out |
If you ported a number in, you can port it out for $40. If local law requires, you can port out a SmartFax-provided number for a fee of $40. |
| RingCentral | YES | SOMETIMES | none | You can port a RingCentral-provided number out but must keep account paid and active during the porting process |
| ClicktoFax | YES | YES | none | |
| Foiply | YES | YES | $15/port in none/port out |
[Verified 4/9/2015]