Phone data guide
Phone number validation
Phone number validation checks a number in layers: format, allocation, carrier and line type, plus a separate reassignment check. In the US the digits cannot show a mobile, because 47.5% of US and Canadian exchanges mix line types. Only a check of the number itself against carrier data says whether it is a cell phone.
By the Leadity team Updated 20 October 2026 11 min read 9 sources How we work
On this page
- Step 1Number formattingChecks the numbering format and standardizes it+1 512 555 0142
- Step 2Number allocationConfirms a valid, allocated numbering rangeAllocated range
- Step 3Carrier lookupIdentifies the carrier from telecom datasetsCarrier found
- Step 4Line-type detectionClassifies the line as one of five typesMobileLandlineVoIPToll-freeOther/unknown
What is phone number validation?
Phone number validation is a stack of checks, not one test. Each check answers a different question, and a number can pass one and fail the next.
Format validation asks if the digits could be real. An allocation check asks if the number sits in an assigned range. A carrier lookup asks which carrier it is with. A line type check asks: mobile, landline, VoIP or toll-free? A separate reassigned-number check asks if it changed hands.
For sales teams the key answer is the line type: is this a cell phone? It decides who picks up, whether a text can land and which calling rules apply.
Format, allocation, carrier, line type or reassigned: what does each check prove?
The four validation steps and the reassigned-number check, compared
| Check | Question it answers | What it reads | What it cannot tell you |
|---|---|---|---|
| Format validation | Could these digits be a real number? | The numbering plan's valid ranges, often with Google's free libphonenumber | Whether a US number is a mobile, or whether anyone answers |
| Allocation check | Is the number in a valid, allocated range? | Numbering records, such as the NANPA block records: the carrier holding the number's block of 1,000 | Whether the number was ported to another carrier later |
| Carrier lookup | Which carrier is it with? | Telecom carrier datasets; a live lookup reads current routing and porting records, one query per number | Whether the person you want still owns it |
| Line type check | Mobile, landline, VoIP, toll-free or unknown? | The carrier's kind, from the allocation and carrier steps | Who answers it, or whether you have consent to call |
| Reassigned-number check | Was it disconnected since a date? | The FCC's Reassigned Numbers Database: yes, no or no data | The line type, or whether you have consent |
One more check, a code sent by text or call, proves someone receives it, but only when they expect it.
Sources Google (libphonenumber) FCC
- Number (813) 555-0129 From the listing
- Step 1: Formatting +1 813 555 0129 Format checked and standardized
- Step 2: Allocation Allocated A valid, allocated numbering range
- Step 3: Carrier Carrier found Identified from telecom datasets
- Step 4: Line type Mobile Kept: it matches the mobile filter The five line types: Mobile (this number), Landline, VoIP, Toll-free, Other/unknown
Can you tell if a number is a cell phone from the digits?
No, not in the US. Mobiles, landlines and VoIP lines share area codes and prefixes, so the digits alone cannot settle it.
Google's libphonenumber, the open-source library many apps use at sign-up, reports US numbers as "fixed line or mobile" instead of guessing.
The exchange, the area code plus the next three digits, is not enough either. 47.5% of US and Canadian exchanges hold more than one kind of line, per Leadity's count of NANPA block records read 22 September 2026.
What this means for you: you cannot spot a mobile from its area code or its first six digits. Leadity checks each number, so you do not have to.
Sources Google (libphonenumber) Leadity
In some regions (e.g. the USA), it is impossible to distinguish between fixed-line and mobile numbers by looking at the phone number itself.
Why does the block, not the exchange, show the assigned line type?
A carrier holds numbers in blocks of 1,000, so one exchange can mix wireless, landline and VoIP blocks, and only the block record says which kind a number was assigned as. Leadity's counts of all 1,539,378 assigned blocks, by state, are in our US phone line types report.
Source Leadity
| Part | Value (%) |
|---|---|
| Wireless | 40.5% |
| Landline | 31.3% |
| VoIP | 28.2% |
Thousand blocks by line type, US and Canada: 1,539,378 blocks, NANPA records read 22 September 2026 (Leadity count).
Source Leadity
When do you need a live carrier lookup?
A live lookup queries current routing records, one number at a time, for the carrier serving it today. For mobiles it is often called an HLR lookup.
A live lookup catches the ports a block lookup misses, but every query costs money. Use it where a wrong label is expensive: before autodialing, before texting at scale, or on an old list.
What is a reassigned number check, and why run one?
A number can be a working mobile and still belong to someone new. About 35 million US numbers are disconnected and made available for reassignment each year, the FCC said in its December 2018 order.
The order created the Reassigned Numbers Database. Give it a number and a date, and it answers yes, no or no data: was the number permanently disconnected since then?
A disconnected number must sit unused for at least 45 days, and a former business number can be held for up to 365 days. Callers pay usage charges to query the database.
If it wrongly answers "no", a caller who queried it has a safe harbor under 47 CFR 64.1200(m), for calls made on consent obtained before.
Sources FCC eCFR (FCC rules)
Four numbers from the calling rules
- 35 million US numbers disconnected and made available for reassignment each year (FCC, 2018) FCC
- 45 days Minimum wait before a disconnected number goes to a new customer; business numbers can wait up to 365 eCFR (FCC rules)
- 15 days TCPA grace window for voice calls to a number newly ported from landline to wireless eCFR (FCC rules)
- 31 days How often sellers who must use the Do Not Call registry refresh their copy FTC
Does the B2B exemption cover calls to business mobiles?
Partly. The FTC says most sales calls to businesses are exempt from the Do Not Call provisions of its Telemarketing Sales Rule.
The B2B exemption is about the registry, not autodialers. The FCC's consent rule for autodialed or prerecorded calls names any cellular number, with no business carve-out.
What counts as an autodialer is a legal question. This guide is not legal advice; ask counsel before you automate.
Sources FTC eCFR (FCC rules)
How many business phone numbers are mobiles?
Fewer than half. Of the numbers listed by 2,782,509 businesses in Leadity's Q3 2026 Google Maps data (1 July to 30 September 2026), 36.8% were mobiles. Another 33.4% were landlines, 25.6% VoIP, 2.5% toll-free and 1.7% unknown.
The share of businesses that list a mobile swings by trade, from 12.6% to 64.2% across 32 trades and 2,241,697 businesses in the same data. A list sold "with phones" says little until each number is classified.
Source Leadity
| Item | Value (%) |
|---|---|
| Mobile | 36.8% |
| Landline | 33.4% |
| VoIP | 25.6% |
| Toll-free | 2.5% |
| Unknown | 1.7% |
Line type of the numbers listed by 2,782,509 businesses in Leadity's Q3 2026 Google Maps data (1 July to 30 September 2026).
Source Leadity
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Is there a free way to validate phone numbers?
Free and paid ways to check phone numbers
| Method | Price | Best for | Watch out for |
|---|---|---|---|
| libphonenumber (Google, open source) | Free | Clean formats in a CRM or a sign-up form | Reports US numbers as fixed line or mobile |
| NANPA block records | Published by NANPA; you map each carrier to a line type | Teams that can code a block-level lookup | Shows the first carrier, not later ports |
| Paid lookup APIs | Per number, e.g. Outscraper's lookup at $5 per 1,000 after 25 free | Bulk lists you already own | You pay for every row, mobile or not |
| FCC Reassigned Numbers Database | Usage charges set by its administrator | Lists built on consent collected earlier | Answers disconnection only, not line type |
| Code by text or call | Per message | Opt-in sign-ups | Needs a person who expects your code |
Outscraper's lookup returns mobile or landline and the carrier; rate from its pages archived 17 to 23 June 2026.
Sources Google (libphonenumber) FCC Outscraper
Which phone check do you need?
If You only need clean, consistent numbers in a CRM
Then Run format validation with libphonenumber and store every number in E.164, the international format.
If You will hand-dial a list and want owners' cell phones
Then Run the format, allocation, carrier and line type checks, then drop landline, VoIP, toll-free and unknown numbers.
If You plan to text or autodial mobiles
Then Confirm consent for each one, run a live lookup for ports and query the Reassigned Numbers Database.
If You are building a new list of local businesses
Then Classify each number while you scrape it, so you never pay for rows you will delete.
- Search Plumbers in Tampa, FL, live on Google Maps Tampa, FL
- Validate numbers Format, allocation, carrier, then line type Mobile Landline VoIP Toll-free Other/unknown
- Filter Keep only the leads you ordered Mobile only
- Export A CSV or Excel file plumbers-tampa-fl.csv
How do you validate a list of business phone numbers?
Normalize every number
Strip spaces, dots and brackets and store each number in E.164. Duplicates show up once formats match.
Tip: Keep the original text in a second column for audits.
Drop what cannot be real
Run format validation, then check each number's range against carrier data and remove any that is not allocated. No paid lookup fixes a typo.
Find the carrier, then the line type
Look up each number's carrier, from its block or with a live lookup. Then tag it mobile, landline, VoIP, toll-free or unknown, and never guess.
Match the list to the channel
Texts need mobiles; hand-dialed calls can use any type. Decide what you keep before you pay for more checks.
Run the compliance checks
Before you autodial or text mobiles, confirm consent, scrub Do Not Call where it applies and query the Reassigned Numbers Database.
Tip: Log the date of every query: the FCC safe harbor depends on it.
Re-check before each campaign
Numbers get ported, disconnected and reassigned, so a label that was right last quarter can be wrong today.
What mistakes break phone number validation?
- Reading the line type from the area code or the exchange
- Counting a VoIP number as a mobile
- Assuming a business mobile is outside the TCPA's cell phone rule
- Reusing an old list without a reassigned-number check
Questions people ask
How do I check if a phone number is a cell phone?
To check if a phone number is a cell phone, look it up, because the digits cannot tell you. 47.5% of US and Canadian exchanges mix line types, per NANPA records read 22 September 2026. The check has four steps: format, allocation, carrier lookup and line type. If the number may have moved carriers, use a live carrier lookup.
Is phone number validation the same as phone verification?
Phone number validation is not the same as verification. Validation checks a number against records, such as its format, allocation, carrier, line type or reassignment, without contacting anyone. Verification proves a person controls the number, usually with a code sent by text or call. Use validation to clean a list, and verification when someone signs up and expects your code.
Can a landline number become a mobile number?
Number portability lets a customer move a landline number to a wireless carrier and keep it. FCC rules give callers 15 days after such a port for voice calls not knowingly made to a mobile, unless the number is on a Do Not Call list. A block lookup still shows the landline carrier; a live lookup catches the move.
Is a VoIP number a mobile number?
A VoIP number is not a mobile number: an internet phone provider holds it, not a wireless carrier, so a line type lookup labels it VoIP and a mobile-only filter drops it. VoIP providers hold 28.2% of the 1,539,378 thousand blocks in the US and Canada, per Leadity's count of NANPA records read 22 September 2026.
Do I need the Reassigned Numbers Database for cold calls?
The Reassigned Numbers Database matters most when you autodial, use a prerecorded voice or text mobiles on consent collected earlier. The FCC safe harbor in 47 CFR 64.1200(m) covers only callers who queried it. About 35 million US numbers are disconnected and made available for reassignment each year. This is not legal advice.
Sources
Where the figures on this page come from, with the date we read each one.
- eCFR (FCC rules) 47 CFR 64.1200 Delivery restrictions (TCPA rules) Read 14 October 2026
- FCC Second Report and Order on reassigned numbers (FCC 18-177, December 2018) Read 14 October 2026
- eCFR (FCC rules) 47 CFR Part 52: 52.15 aging numbers, 52.20 thousands-block pooling, 52.21 definitions Read 14 October 2026
- Google (libphonenumber) libphonenumber: README, FAQ and PhoneNumberUtil.java Read 14 October 2026
- FTC Q&A for Telemarketers and Sellers About DNC Provisions in the TSR Read 14 October 2026
- Leadity Leadity's Q3 2026 Google Maps data (1 July to 30 September 2026) Read 20 October 2026
- Leadity US phone line types: NANPA thousand-block records, counted (read 22 September 2026) Read 22 September 2026
- Outscraper Outscraper pricing pages, archived 17 to 23 June 2026 Read 23 September 2026
- Google (libphonenumber) libphonenumber: PhoneNumberUtil.java (PhoneNumberType comments) Read 14 October 2026
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