Typical Fax Error Rates

Our faxing system has about a 1% error rate to a traditional analog or digital lines. Unfortunately, many endpoints are poorly designed fax over IP (FoIP) endpoints.  So, adding VoIP faxes to and from us, the error rate is 5% outbound and 8% inbound. Our faxing system is also monitored so errors due to a failure of our fax servers are cleared immediately.

When faxes fail, it is typically a single fax source that says “We can’t send a fax”.

The Failed Fax Send Error Reduction Process

  • We provide you a second fax number designed to take a different call path to our servers. Most of the time, this 2nd number works.
  • Do only large faxes, over 500 pages fail?
    • Many times these are mechanical issues with a paper feeder.
    • We will send to ourselves a fax of the same size from a  third party “electronic fax” service.  This is a fax not sourced from a stack of papers in a hopper.
  • We will take a manual read of our error rates.
  • The remaining focus is on the sender.
    • Ask the sender to reboot their fax machine or server.
    • We establish a permanent 3rd fax number for you on a fax system run by another company. If this fails, we can say two independent systems, with nothing but the sender fax in common, can not receive the senders fax.

At this point, the issue is with the sender’s fax machine. We can help further but only if the above data is acknowledged.

Observations from our industry peers say a 6% error rate is typical

Fax transmission is an analog technology. It’s modem tones transmitted over a phone line at around 2100 hz. In the old days of analog lines, what fax is based on, we saw error rates of 6%. Like making a copy of an (analog)  cassette tape, analog fax tones can be compressed and re-transmitted that yield literally a poor sounding copy of the original fax transmission.  Today, in the day of voice over IP VoIP and without our services,  we see as much as a 20% error rate. Beyond our data, below is third party evidence.

” no one will sign off on it but you are looking at 5 – 7%”  – industry expert. We can play the name of this person and company privately.

… googling the phrase https://www.google.com/search?&q=typical+facsimile+error+rate


“When attempting to send real-time faxes over an IP network that is operating under normal conditions, a success rate of 80% is reasonable for single-page faxes. ”



“Traditional analog faxing has roughly a 5% failure rate; e-faxing has a slightly higher failure rate around 5-8% due to the additional steps necessary with a fax server. ”



“Fax over internet, FoIP, had formerly been unable to achieve a transmission success rate of more than 85%