Glossary
What is a carrier lookup?
A carrier lookup tells you which phone company currently holds a number, and usually whether it is a mobile, landline, VoIP or toll-free line. Because numbers can be ported between carriers, the area code alone cannot tell you this.
The terms behind a carrier lookup
| Carrier | The phone company (or service provider) that currently provides service for a number, such as a mobile network, a landline company or a VoIP provider. |
| Carrier lookup | A check that returns the current carrier of a phone number, usually together with its line type (mobile, landline, VoIP or toll-free). |
| Number portability | The rule that lets people keep their number when they switch providers. Because of it, the area code and prefix do not reliably tell you the current carrier. |
| Original carrier | The carrier the number block was first assigned to. A ported number can now be with a different carrier. |
| Line type | The kind of line behind the number: mobile, landline, VoIP or toll-free. It often comes back with the carrier. |
How a carrier lookup works
Every US number starts out in a block assigned to one carrier. When a subscriber switches providers and keeps the number, the move is recorded in number portability data. A carrier lookup checks that carrier data for the number's current provider and line type, instead of guessing from the prefix.
That is why two numbers with the same area code and prefix can come back with different carriers: one may have been ported.
Why carrier lookups matter if your team calls or texts leads
- Texting: SMS campaigns work on mobile numbers. Knowing the line type first keeps landlines out of text sends.
- Dialer routing: many teams treat mobile, landline and VoIP numbers differently in their dialer or CRM.
- Not a compliance check: a carrier lookup says nothing about Do Not Call status or consent.
Prefix guess vs. carrier lookup
| Area code + prefix | Carrier lookup | |
|---|---|---|
| Answers | Who was this number block originally assigned to? | Who holds this number now, and what kind of line is it? |
| Ported numbers | Often wrong, because the number may have moved | Reflects the current carrier from carrier data |
| Line type | A guess based on the block | Mobile, landline, VoIP or toll-free |
| Valid or dead | No | Depends on the provider. TrueSearch returns valid or dead |
What TrueSearch returns, and does not
| Valid or dead (disconnected / not assigned) | Yes, every number |
| Line type: mobile, landline, VoIP, toll-free | Yes, every number |
| Carrier name | Yes, every number |
| Bulk upload (CSV or Excel) | Yes, results in about 30 seconds per 1,000 numbers |
| REST API | Yes (JSON, one API key) |
| Claude / ChatGPT / Cursor connector (MCP) | Yes |
| National or state Do Not Call check | No, not yet |
| Known TCPA litigator check | No, not yet |
| FCC Reassigned Numbers Database check | No |
| Starting price | $97/month for 5,000 numbers, 7-day free trial |
| One-off list | $20 per 1,000 numbers, no subscription |
Upload a CSV or Excel file. Every number comes back valid or dead, mobile, landline, VoIP or toll-free, with carrier.
Starter: $97/month for 5,000 numbers after the 7-day trial. Cancel anytime.
Questions
What is a carrier lookup?
A carrier lookup is a check that tells you which phone company currently holds a phone number, and usually what kind of line it is (mobile, landline, VoIP or toll-free). It answers "who is this number with right now?" rather than "who was it assigned to originally?"
Why can't I tell the carrier from the area code?
Because of number portability. In the US, people can keep their number when they switch providers, so a number first assigned to one carrier can now be with another. The area code and prefix only tell you where and to whom the number block was first assigned.
Why do sales and marketing teams use carrier lookups?
To route numbers correctly: texts go to mobile numbers, landlines may be handled differently by dialers, and VoIP or toll-free numbers may need their own rules. Knowing the line type and carrier before a campaign helps teams avoid wasted dials and failed texts.
Is a carrier lookup the same as an HLR lookup?
Not exactly. A carrier lookup returns the current carrier and line type and works on any US number. An HLR lookup queries a mobile network directly and only covers mobile numbers. See our page on HLR lookups for the details.
Does a carrier lookup tell me who owns the number?
No. A carrier lookup returns the phone company and line type, not the name of the person or business using the number. Caller ID names come from CNAM databases, which are a separate thing.
Can I do a carrier lookup for free?
Yes. Our free carrier lookup tool checks one US number at a time and shows carrier, line type and whether the number is valid. For whole lists, TrueSearch for Business checks every number by CSV upload or REST API.
Does TrueSearch check Do Not Call status?
No. TrueSearch checks validity, line type and carrier only. For Do Not Call status, use the National Do Not Call Registry at donotcall.gov.
Related: free carrier lookup tool, what is phone line type?, what is a ported number?, what is an HLR lookup? and what is CNAM?
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This guide is general information, not legal advice. TrueSearch for Business checks validity, line type and carrier from licensed telecom data. It does not check the National Do Not Call Registry, state DNC lists or the FCC Reassigned Numbers Database. Not a consumer reporting agency; not for FCRA purposes.