In depth
What the three results mean
A list check gives each number one of three results. Valid means the length and the digits fit a range that is assigned in that country. Possible means only the length fits. Invalid means the length does not fit. The library's author prefers the length-only check for forms, because numbering plans change and an old copy of the library could reject a newly assigned range. For a list you are about to message, the stricter valid result is the safer one to keep.
| Input | Result | E.164 or reason | Why |
|---|---|---|---|
| (213) 373-4253 (US) | Valid | +12133734253 | A normal local number. |
| 213-373-425 (US) | Invalid | TOO_SHORT | One digit missing. |
| 000 000 0000 (US) | Possible | +10000000000 | Right length, but no such range exists. |
| +44 20 7946 0958 | Valid | +442079460958 | International number, no default country needed. |
| 020 7946 0958 | Unreadable | INVALID_COUNTRY | No plus sign and no default country. |
| Call: (213) 373-4253 (US) | Unreadable | NOT_A_NUMBER | Text around the number. |
A safe way to clean a list
Work in this order so you never lose data.
- Pick the right default country first. A list of local numbers is only readable in one country at a time.
- Run the list and download the CSV. It keeps your original text next to the result.
- Keep the valid rows. Review the possible rows by hand, because they are usually typos in the first digits.
- Remove duplicates by the E.164 column, not by the original text, because +44 20 7946 0958 and 020 7946 0958 are the same number.
- Import only the E.164 column into your system.
Limits and privacy
The tool checks up to 2,000 lines per run, all in your browser. Nothing is uploaded, so there is no file size limit set by a server and no copy of your list left behind. Cells that begin with = + - or @ are protected in the CSV so a spreadsheet cannot run them as formulas, except plain phone numbers that start with +.