VoIP number checker
Enter a US phone number and this tool looks up what kind of line it is: mobile, landline, fixed VoIP or non-fixed VoIP, and the carrier it is with now. Apps run the same kind of lookup before they text a verification code, and many refuse a number that comes back as VoIP. It is free, needs no account, and checks up to 5 new numbers an hour.
Checked by VerifyWith on
What each result means for a verification code
| Result | What kind of line it is | For a texted code |
|---|---|---|
| Mobile | A mobile carrier’s line, the kind in a phone with a SIM | Generally receives texts; not refused for being VoIP |
| Landline | A fixed line | Not VoIP, but a landline generally can’t receive texts |
| VoIP (fixed) | An internet phone line tied to a physical device, such as a cable or home phone service | Some apps accept it, some refuse it |
| VoIP (non-fixed) | An internet number obtained online, with no physical device behind it | The kind apps refuse most often |
| Toll-free | An 800-style number that is free to call | Rarely accepted for a personal account |
| Unknown | A valid number with no line type on record | No way to tell from the lookup |
The line types and their descriptions follow Twilio’s Lookup documentation, the service this tool asks. Its own examples of non-fixed VoIP include Google Voice numbers.
How a VoIP check works, and where it can be wrong
Every US number belongs to a block that was assigned to a carrier, and numbers can later be moved to another carrier. Lookup services keep records of both and answer with the carrier a number is with now and the kind of line that carrier provides. This tool sends the number you enter to one such service, Twilio Lookup, and shows its answer.
Three limits are worth knowing before you rely on a result:
- Lookup services can disagree. An app may ask a different service from the one this tool asks, and the two can classify the same number differently.
- Line type is one check among several. An app can also refuse a number because it was used on too many accounts, because of the country it belongs to, or for reasons it doesn’t publish. A “mobile” result is not a promise that an app accepts the number.
- The lookup says nothing about who uses the number. It names a carrier and a line type, not a person, an address or whether the number is in service.
Why apps look at line type at all is covered in why apps reject VoIP numbers.
When checking a number is worth it
- An app just refused your number. If the result is VoIP, the line type is the likely reason, and a different VoIP number will probably be refused too. If the result is mobile, the cause is something else: see “this number cannot be used for verification”.
- You are about to pay for a number. If a seller shows you the number first, check it before you buy. A seller that calls its numbers “non-VoIP” should be able to pass this check. Our guide to buying a non-VoIP number lists the other things to check.
- You are building a sign-up form. The check shows what your own verification provider is likely to see for a given number.
A number rented from us is non-VoIP, and you can check it here like any other once you have it. That is still not a promise about any one app, for the reasons above.
Limits, and what happens to the number you enter
Each new lookup costs us money, so the tool checks up to 5 new numbers an hour and 15 a day from one connection or one browser. Checking the same number again within a week doesn’t count, because we keep the answer. It checks US numbers only: +1 numbers in Canada or the Caribbean are turned away.
The number you enter is sent to our server and from there to Twilio, to get the answer. We don’t store the number itself or write it to our logs. We keep the answer for a week, filed under a one-way hash of the number, so a repeat check needs no second lookup. The tool is for checking a line type. It doesn’t find a number’s owner, and it shouldn’t be used to build lists of numbers.
To keep scripts from running up lookups, the page uses Cloudflare Turnstile to check that a person is asking, and sends a hash of some of your browser’s settings so the limit counts per browser. We use that hash for the limit and nothing else, and it is gone within a day.
Questions people ask
- How can I tell if a phone number is VoIP?
- Look it up in a carrier database. A number’s line type isn’t visible in its digits: a VoIP number and a mobile number can share an area code. Enter a US number above and the tool shows whether the lookup classes it as mobile, landline, fixed VoIP or non-fixed VoIP.
- What is the difference between fixed and non-fixed VoIP?
- Both are internet phone lines. A fixed VoIP number is tied to a physical device or service address, like a cable company’s home phone. A non-fixed VoIP number is obtained online with no physical device behind it. Apps that refuse VoIP numbers refuse the non-fixed kind most often.
- Is a Google Voice number VoIP?
- Yes. Twilio’s Lookup documentation gives Google Voice as an example of non-fixed VoIP, which is why some apps won’t send a verification code to one.
- Can a VoIP number receive verification codes?
- Technically yes: many VoIP numbers receive texts. Whether a code is sent is the app’s choice, and some apps refuse to text a number their lookup classes as VoIP. Each app’s published rule is in our table of which apps accept virtual numbers.
- Is the result always right?
- No. It is one lookup service’s record of the number’s carrier and line type. Records lag when a number moves between carriers, and another service can class the same number differently, so an app may see something else.
- Does the checker work for numbers outside the US?
- No. It checks US numbers only. Numbers in other countries, including +1 numbers in Canada and the Caribbean, are turned away.
Sources
Read on November 13, 2026. Prices and policies change; if something here is out of date, write to [email protected] and we’ll correct it.