Ofcom Range Holder Lookup — Find Who Owns Any UK Number

A range holder lookup answers a deceptively useful question: *which Communications Provider did Ofcom allocate this block of UK phone numbers to?* The answer is the single most useful first signal you can get about an unknown UK caller — it tells you whether a number was issued by BT to a residential line, by a major mobile network, by a wholesale VoIP carrier, or by a personal-numbering reseller of the kind that scammers favour. The lookup is free, deterministic, and works for every UK landline, mobile, freephone, service and personal number — including ported ones.

#What is an Ofcom range holder?

Ofcom — the UK telecoms regulator — doesn't give individual phone numbers to consumers. Instead, it parcels the entire UK numbering plan into blocks: usually 1,000 or 10,000 consecutive numbers inside a given dialling code. Those blocks are allocated to licensed Communications Providers (CPs) under the National Telephone Numbering Plan. The CP that holds a block is called the range holder for that block.

Range holders fall into a handful of categories you'll see again and again in the lookup results on this site:

• Retail mobile networks — EE, O2 (Telefónica), Three (Hutchison 3G UK), Vodafone, BT Mobile, Sky Mobile, Tesco Mobile, giffgaff (operating on O2). These hold the bulk of 071–079 mobile ranges.
• Fixed-line incumbents — British Telecommunications PLC (BT), Virgin Media, Sky, TalkTalk. These hold most 01/02 residential and small-business ranges.
• Wholesale and B2B carriers — Gamma Telecom, Daisy Communications, Magrathea Telecommunications, Voxbone / Bandwidth, BT Wholesale. These sub-allocate to thousands of resellers who in turn issue numbers to VoIP, contact-centre and SaaS customers.
• Service-number specialists — Phone-paid Services Authority (PSA)-registered holders for premium-rate ranges, charity-helpline aggregators for the freephone block, and a handful of personal-numbering providers for the 070 range.
• Government and emergency — BT (for 999 / 112 routing), NHS Digital (for the 111 short code), various government bodies for the 03x non-geographic blocks they publish.

#How to look up a UK range holder (the 30-second version)

Three options, in order of speed:

1. 1

   Option 1 — use the lookup on this site

   Paste any UK phone number into the search box on the homepage of WhoCalledLookup. The result page returns the range holder, the prefix, the allocation status (Assigned / Reserved / Free / Withdrawn / Recovered) and the principal town in under two seconds. No signup, no card, no daily limit.

2. 2

   Option 2 — search the Ofcom Numbering Data feed directly

   Download the latest weekly spreadsheet from Ofcom's Numbering Data page, open the relevant area-code workbook, and look up the prefix. Free but slow — you'll be scanning a 100,000-row Excel file. Useful for due-diligence or compliance reasons where you want the raw record.

3. 3

   Option 3 — query a carrier-signalling API

   For high-volume, programmatic checks (CRM hygiene, fraud scoring, signup validation), paid APIs such as Twilio Lookup or Vonage Number Insight return the range holder alongside live HLR data. Charged per query; usually <£0.01 per lookup. Pick this only if you're checking more than a few hundred numbers a month.

#What the range holder result actually tells you

A successful range holder lookup returns five fields. Each one carries a different signal &mdash; understanding what they mean is the difference between confidently ignoring a missed call and ringing back a wangiri scam.

#Allocation statuses you might see and what they mean

Most ranges return Assigned &mdash; the block is live and the CP has issued the numbers to customers. The other statuses each have a specific meaning that's worth recognising:

• Assigned — the block is in active use. Calls from this range are expected.
• Reserved — the CP has Ofcom permission to use the block but hasn't activated it yet. Calls from this range are unusual but not impossible if activation happened between weekly Ofcom updates.
• Protected — Ofcom is intentionally holding the block back from allocation (often to keep certain digit patterns out of public circulation). Calls from a Protected range almost always indicate spoofed CLI.
• Free — the block was once allocated but is now available for re-allocation. No CP currently owns it, so nothing should be dialling from it. If a call comes in from a Free range, treat the CLI as spoofed.
• Recovered — a block that has been pulled back by Ofcom after the original holder failed to use it or returned it. Same scam-risk implication as Free.
• Withdrawn — the block has been removed from the numbering plan altogether (typically when an old prefix is retired). Calls from a Withdrawn range cannot legitimately originate — always spoofed.

#Why the range holder matters for scam detection

Most UK scam calls come from one of three sources, and each leaves a distinctive fingerprint in the range holder data:

1. Spoofed CLI — the scammer is using SIP/VoIP gear to inject any caller ID they like. They tend to spoof banks (a 0345 / 0203 / 0800 a victim might recognise) or government numbers. Range holder lookup catches this when the spoofed number sits in a Free / Protected / Reserved range — there's no real CP behind it.
2. Cheap personal-numbering blocks — a fraudster buys a cheap 070 block from a personal-numbering reseller, uses it for 24–48 hours of wangiri (one-ring) calling, and discards it. Range holder lookup catches this because the holder name is rarely a household network — it's typically a small reseller you've never heard of.
3. Legitimate but spammy — cold-call telemarketing from a real CP holder, often a wholesale VoIP carrier that resells to call-centre clients. Range holder lookup catches this by showing a wholesale/reseller name (Gamma, Magrathea, Voxbone) rather than a retail brand.

None of those three signals are conclusive on their own, but combined with the line type, the area code and the AI internet check, they're enough to make a confident judgement on whether to ring back. The lookup tool on this site presents all five signals on one result page so you don't have to cross-reference them yourself.

#How the data on this site is sourced and refreshed

Every range-holder result on WhoCalledLookup comes from Ofcom's official National Telephone Numbering Plan and the weekly Numbering Data feed it publishes. The pipeline:

1. 1

   Ofcom publishes a new Numbering Data spreadsheet every Wednesday

   The file lists every 1,000- and 10,000-number block in the UK numbering plan, the dialling code it sits inside, the current CP holder, the allocation status (assigned / reserved / free / protected / recovered / withdrawn), and the date of the last allocation change.

2. 2

   Our ingest pipeline downloads and parses the spreadsheet within hours of publication

   A weekly systemd timer pulls the latest workbook, deduplicates CP names against the master holder table, normalises slug formats, and writes the result into the database used by every page on this site.

3. 3

   The lookup endpoint queries the live database

   When you paste a number into the search box, the request matches the number against the longest applicable prefix (10,000-block first, then 1,000-block fallback) and returns the current holder. The result is cached for 24 hours per number for speed.

4. 4

   Per-number history pages are updated as soon as the underlying allocation changes

   If Ofcom re-allocates a block to a different CP, the per-number pages we publish for the affected numbers update on the next revalidation pass (within an hour). The historical holder for each number is preserved so you can see the allocation timeline.

Practically, that means every range holder lookup on this site is at most seven days old — the gap between Ofcom's weekly publication and the next refresh. That's substantially fresher than commercial third-party 'WHOIS for phone numbers' services that scrape the same source on a quarterly cycle.

#Range holder lookup vs the alternatives

#Frequently confused: range holder vs caller ID vs network

Three different things, often conflated, but each tells you something different:

• Range holder — the CP Ofcom allocated the block to. Static unless Ofcom re-allocates. The one returned by this site's lookup.
• Current carrier — the network actively routing calls to the number today. Changes when a customer ports the number. Only available via paid carrier-signalling APIs.
• Caller ID (CLI) — the number displayed on the recipient's phone. Set by whoever is placing the call — trivially spoofable by VoIP, which is why CLI alone is not trustworthy.

The right hierarchy for trusting a UK incoming call is: caller's words < CLI < range holder lookup < AI internet check + community reports. Each layer adds confidence; the lookup on this site does the bottom three of those four in one click.

#When to use a range holder lookup

Concrete situations where the result genuinely changes what you do next:

• Unknown 07 mobile number called you — lookup tells you the network (EE, O2, Three, Vodafone, Sky, BT) and whether the number is in active allocation. A real 07 number on a real mobile network = probably a courier, delivery driver, salon booking, dentist, or someone you actually know.
• Suspicious 020 / 0203 / 0207 number claims to be your bank — lookup tells you whether the range is held by your bank's published telecoms provider. If it isn't, the CLI is almost certainly spoofed. Hang up and dial 159.
• Missed call from an 070 'mobile' you don't recognise — lookup tells you it's a personal-numbering line, not a mobile, and warns about the up-to-50p-per-minute call cost. Don't ring back.
• Sales call from a number you've blocked before — lookup tells you the wholesale CP behind the reseller, so you can report the call to that CP's abuse address and force them to action it.
• Cold call claims to be Ofcom or another regulator — lookup confirms the range holder isn't actually Ofcom (Ofcom doesn't run a consumer dialler at all). Strong tell that the call is impersonation.

#Bottom line

An Ofcom range holder lookup turns an opaque UK phone number into a small, verifiable record: which CP owns the block, what the prefix is, whether the allocation is currently active, and (for landlines) what town the dialling code anchors on. That single record tells you 80% of what you need to know about an unknown incoming call — the remaining 20% is whether the open web has flagged the number, which the AI internet check on this site adds for free in the same request. Paste any UK number into the form on the homepage to try it.