This has to be one of the stupidest "features" that some developer thought would be a "bright idea" to incllude in Firefox. Yes, I know that the country code is needed if direct dialing a US phone number from many countries (not all, but many), and yes, there are many places in the world where including a country code is readily recognized (I have never seen or heard of anywhere that a country code is routinely included, but within the international business community at least country codes are recognized and understood). I hate to have to try to tell the team at Mozilla the facts of life, but more of your customers are in the USA than in any other country. We have US phone numbers and ''we use autofill '''on web forms in the USA'''''. I fill out about two dozen different online forms every day. I have yet to ever see even a single online form that needed the US country code, but I have seen that the vast majority of online forms will not accept the US country code''!'' Most online forms in the US that ask for a phone number are configured to accept (and often require) a 10-digit phone number. Some of these forms will simply ignore non-numeric characters, but other forms completely reject phone numbers that include non-numeric characters. Very few forms recognize the +1 as a country code. Most either see that the data being entered is not a valid 10-digit phone number and reject it outright or they accept the first 10 numeric characters. If a form accepts the first 10 numeric characters it creates a significant problem.... The Firefox user has entered and saved an autofill address with a phone number of 5025551212 Firefox changes that phone number to +15025551212 Firefox autofills that phone number into a form The form reads the first 10 numbers and saves the phone number as 1502555121 Thus the user's (502) 555-1212 has magically become (150) 255-5121 which is wrong in many ways. I suppose in a decade or two, perhaps the US country code might become accepted as part of a phone number, or perhaps programmers writing online forms might learn to recognize (and discard) the +1 but I wouldn't count on it. If anyone at Mozilla really thinks adding the +1 is a good idea, '''''please''' at least offer us the option to NOT use it''