Use E.164
A plus sign, the country dial code, then the subscriber number — no spaces, dashes, brackets or leading zeros. +447400000123, not +44 (0)7400 000 123.
200+ countries
E.164 formatting
Validate International Lists Without Format Errors
Most “failed” international checks are not failures. They are numbers that were never formatted into something WhatsApp could recognise. This is the reference we use ourselves.
07400 000123 → +447400000123United Kingdom · leading 0 dropped
Fixed
0151 0000 8842 → +4915100008842Germany · leading 0 dropped
Fixed
340 000 4412 → +393400004412Italy · no trunk prefix to drop
Note
The one rule
E.164, and mind the trunk prefix
Get this right and the majority of international validation problems disappear.
Drop the trunk prefix
The digit you dial inside a country, usually a 0. It exists only for domestic dialling and must be removed when converting to international format.
Except where there is none
Italy, Spain, India, Mexico and Poland have no trunk prefix. Stripping a digit there breaks a perfectly good number.
The classic double-fault: +4407400000123 — someone added the country code but left the trunk prefix in place. It looks plausible, it fails every check, and it is the single most common defect in UK lists we see.
Priority markets
The markets teams ask about most
Formatting rule, what to expect from your active rate, and the regulator whose rules govern outreach there.
GB+44
United Kingdom
Mobiles start 07 domestically. Drop the zero.
- High WhatsApp adoption — expect a strong active rate
- Watch for
+44(0)artefacts pasted from websites - UK GDPR and PECR, enforced by the ICO
US+1
United States
Ten digits, no trunk prefix. The area code is part of the number.
- Low adoption — a modest active rate is normal here
- Landlines and VoIP are mixed into most US lists
- TCPA and state law — consent rules are strict
DE+49
Germany
Mobiles start 015, 016 or 017. Drop the zero.
- Mobile length varies — do not assume a fixed digit count
- High adoption; a primary messaging channel
- GDPR plus the UWG — among the strictest markets
NL+31
Netherlands
Mobiles are 06 plus eight digits. Drop the zero.
- Very consistent format — Dutch lists normalise cleanly
- High adoption, widely used for business contact
- GDPR plus the Telecommunicatiewet
BE+32
Belgium
Mobiles start 04 domestically. Drop the zero.
- Easy to confuse with Dutch numbers — split by dial code first
- Three language regions — segment by language, not country
- GDPR, enforced by the Belgian DPA
AE+971
United Arab Emirates
Mobiles start 05 domestically. Drop the zero.
- Very high adoption across the Gulf
- Large expatriate population — mixed-language audiences
- Local telecom and data rules apply
Reference
Dial codes and formatting rules
The markets our users validate most. Cloud checking covers 200+ countries beyond this list.
| Country | Dial code | Mobile starts | Drop leading 0? | E.164 example |
|---|---|---|---|---|
| United Kingdom | +44 | 07… | Yes | +447400000123 |
| United States | +1 | Area code | No prefix | +14150008821 |
| Canada | +1 | Area code | No prefix | +16470008821 |
| Germany | +49 | 015/016/017… | Yes | +4915100008842 |
| Netherlands | +31 | 06… | Yes | +31610004412 |
| Belgium | +32 | 04… | Yes | +32470004412 |
| France | +33 | 06/07… | Yes | +33610004412 |
| Spain | +34 | 6/7… | No trunk prefix | +34612004412 |
| Italy | +39 | 3… | No trunk prefix | +393400004412 |
| Switzerland | +41 | 07… | Yes | +41790004412 |
| Austria | +43 | 06… | Yes | +436640004412 |
| Poland | +48 | 9 digits | No trunk prefix | +48510004412 |
| Australia | +61 | 04… | Yes | +61400004412 |
| United Arab Emirates | +971 | 05… | Yes | +971500004412 |
| Saudi Arabia | +966 | 05… | Yes | +966500004412 |
| Turkey | +90 | 05… | Yes | +905300004412 |
| India | +91 | 10 digits, 6–9 | No trunk prefix | +919800004412 |
| Pakistan | +92 | 03… | Yes | +923000004412 |
| Brazil | +55 | Area + 9 | Yes | +5511900004412 |
| Mexico | +52 | 10 digits | No trunk prefix | +525500004412 |
| South Africa | +27 | 0… | Yes | +27820004412 |
| Nigeria | +234 | 0… | Yes | +2348030004412 |
| Indonesia | +62 | 08… | Yes | +628120004412 |
Example numbers are illustrative, not real subscriber numbers. Numbering plans change — treat this as a starting point and validate against a library such as libphonenumber in production code.
Reading your results
Active rates are not comparable across countries
A 40% active rate can be excellent in one market and a red flag in another.
Compare to the right baseline
WhatsApp is a primary channel across much of Europe, Latin America, South Asia and the Middle East. Judge each country against its own baseline, never against your best market.
Split before you judge
Separate mixed lists by dial code first. A blended active rate across ten countries tells you nothing actionable about any of them.
A sudden drop is usually upstream
When one country’s rate falls abruptly, the cause is almost always a formatting change in the source system, not a change in the audience.
Go deeper
The detail, if you want it
Segment by country before you send, not after
Once numbers carry a detected country and dial code, you can split campaigns by market and get three things almost for free:
- Sending inside local working hours.
- Messaging in the right language.
- Applying whichever consent rules actually govern that market.
Cloud validation returns the country alongside the active flag precisely so this split is a filter rather than a research project.
Compliance differs far more than formatting does
Formatting rules vary in small, mechanical ways. Marketing law varies enormously.
Germany’s UWG and the EU GDPR set a high bar for prior consent. The UK adds PECR on top of UK GDPR. The US TCPA operates on entirely different principles again. Validating a number tells you it exists — it says nothing about whether you may lawfully contact it.
This is not legal advice. We build validation tools, not compliance programmes. Before running outreach into a new market, get qualified local advice on consent, record-keeping and opt-out handling. Our terms set out the responsible-use conditions that apply to our software.
Why US active rates look low — and why that is fine
WhatsApp adoption in the United States is much lower than in Europe, Latin America or South Asia, because SMS and iMessage dominate there.
A US list returning a modest active rate is usually reporting reality accurately rather than indicating a data-quality problem. The actionable response is to route the unverified segment to SMS or calls, not to re-check the list hoping for a different answer.
Quick answers
Frequently asked
Can I check WhatsApp numbers from any country?
Yes. Cloud validation covers 200+ countries with localised routing, and desktop filtering works on whatever your account can reach. Both require full international format with the correct dial code.
Why do so many UK numbers fail?
The leading zero was kept. +4407400000123 is invalid; +447400000123 is correct.
Can I tell which country each number belongs to?
Yes — cloud validation returns the detected country and dial code with every record, which makes splitting a mixed list into per-market segments a simple filter.
Does one tool work for all countries at once?
Cloud checking does, because routing is handled per country server-side. A single logged-in desktop account is inherently more limited on a list spanning many markets.
Validating a multi-country list?
One logged-in account is a poor fit for a list spanning ten countries. Cloud checking uses localised routing per country and returns the detected country with every record — so segmentation comes free with validation.
$1 per 40,000 checks — a 250,000-row international list costs about $6.25.