Phone Number Parser

Phone numbers look simple. They're not. The same 8-digit string can be valid in Singapore (where mobile numbers are 8 digits starting with 8 or 9), simultaneously invalid in Malaysia (10-11 digits), and ambiguous in Indonesia (numbers start with 0, dropped when written internationally). Add international prefixes (+65, +60, +62), local trunk prefixes (the 0 you dial domestically but drop internationally), carrier-specific number ranges, and the difference between mobile, fixed-line, VoIP, and premium-rate numbers — and you have a parsing problem complex enough that Google maintains a dedicated open-source library to handle it. libphonenumber ships in C++, Java, JavaScript, Swift, Ruby, and Python; this tool uses the JavaScript port, self-hosted from this domain.

E.164 — the international standard

E.164 is the ITU-T recommendation that defines the modern international phone number format. An E.164 number is + followed by the country code, followed by the national subscriber number, with a maximum of 15 digits total. +6591234567 is a Singapore mobile number in E.164. The format has no spaces, dashes, or parentheses. Every SMS gateway, WhatsApp Business API, Twilio integration, Stripe Connect verification, and modern CRM expects numbers in E.164. Storing phone numbers in any other format leads to deduplication failures, SMS delivery problems, and inability to route calls. The rule: store E.164, display national.

ASEAN country codes and carrier prefixes

Quick reference table for the region:

• Singapore (+65): 8-digit subscriber number. Mobile starts with 8 or 9; fixed-line starts with 6.
• Malaysia (+60): 7-9 digit subscriber number. Mobile starts with 1 (e.g. 011, 012, 013, 014, 016, 017, 018, 019); fixed-line starts with 2-9 by region.
• Indonesia (+62): 8-12 digit subscriber number. Mobile starts with 8; fixed-line by region (Jakarta is 21).
• Thailand (+66): 8-9 digit subscriber number. Mobile starts with 6, 8, or 9; fixed-line by region.
• Philippines (+63): 10-digit subscriber number. Mobile starts with 9; fixed-line varies by carrier and region.
• Vietnam (+84): 9-10 digit subscriber number. Mobile starts with 3, 5, 7, 8, or 9 (re-allocated on 15 September 2018 — Viettel's 0163 became 033 and VinaPhone's 0123 became 083).

The trunk prefix gotcha

Most countries (including all of ASEAN) have a trunk prefix that you dial domestically but drop when calling internationally. In Singapore, you dial 91234567 (without 0). In Malaysia, you dial 012-345 6789 — the leading 0 is dropped when written internationally as +60 12-345 6789. In Indonesia, the local form 0812 3456 7890 becomes +62 812-3456-7890 internationally. Confusion between these two forms is the single most common phone-number bug in ASEAN integration projects. The tool above normalises everything to E.164 so you don't have to remember which countries strip 0 and which don't.

Why libphonenumber is the standard

Google's libphonenumber is an open-source library for parsing, formatting and validating international phone numbers. It encodes country-specific rules — which prefixes mean mobile or fixed-line, valid lengths, formatting patterns — as metadata that has to be refreshed as countries renumber. This tool uses libphonenumber-js, an independent, smaller JavaScript rewrite built on Google's metadata — its full-metadata build (236 KB), the one that can tell mobile from fixed-line, served from this site's own domain, no third-party CDN.

Numbers that look valid but aren't

Three traps: the number is well-formed but assigned to a non-existent prefix (libphonenumber knows current allocations and will flag these); the country code is correct but the trunk-prefix zero is still attached (e.g. +44 0207… should be +44 207…); or the number is a "test" range deliberately reserved for documentation (UK 020 7946 0xxx, US 555-0100 to 555-0199). The parser surfaces these as invalid even when the digit count looks plausible.