The four parts of an international number
Every international call has the same shape: exit code, country code, area code, subscriber number. The exit code depends on where you are standing, not where you are calling. From the United States and Canada it is 011; across most of Europe, Asia, Africa and Oceania it is 00; Australia uses 0011 and Japan 010. Russia and Kazakhstan are unusual in using a two-step 8 then 10.
On any mobile phone, the plus symbol replaces the exit code entirely. Hold the 0 key until a + appears, then dial the country code and the rest. This is the reliable option because a number stored with a leading + works from any country you happen to be in, whereas a number stored with a hard-coded 011 works only from North America. If you save one international number today, save it with the plus.
The leading zero, and the four countries that break the rule
Most of the world writes national numbers with a leading 0 that is a domestic trunk prefix rather than part of the number. London is written 020 7946 0958 and dialed from abroad as +44 20 7946 0958. The same applies to Germany, France, Australia, Japan, Vietnam, South Africa and dozens of others. Getting this wrong is the single most common failed-call cause, because the number appears to be dialed exactly as written and simply does not connect.
| Case | Written locally | Dialed internationally |
|---|---|---|
| The usual rule | 020 7946 0958 (UK) | +44 20 7946 0958 |
| Italy keeps its zero | 06 1234 5678 | +39 06 1234 5678 |
| Russia, Kazakhstan: trunk is 8 | 8 495 123 4567 | +7 495 123 4567 |
| Hungary: trunk is 06 | 06 1 234 5678 | +36 1 234 5678 |
| No trunk prefix at all | 612 3456 (Singapore) | +65 612 3456 |
Countries with no trunk prefix — Spain, Portugal, Denmark, Norway, Czechia, Poland, Singapore, Hong Kong, and the whole North American plan — need nothing removed: the number as written is the number you dial after the country code.
Country code 1 and country code 7 cover more than one country
The North American Numbering Plan puts the United States, Canada and about twenty Caribbean and Pacific territories inside +1, separated by area code: Jamaica is 1-876, the Dominican Republic 1-809, Puerto Rico 1-787, Guam 1-671. From within the plan these are dialed like domestic long distance, 1 plus ten digits, with no exit code involved. That does not make them free or cheap — several Caribbean area codes carry international or premium rates from US carriers, and a few have been used in premium-rate scams that rely on the number looking domestic.
Country code 7 is shared by Russia and Kazakhstan on the same principle. Codes are also occasionally retired and reassigned; the numbering plan is a living thing, not a fixed table.
Numbers that are not really phone numbers
Toll-free ranges do not cross borders. A US 800, 833, 844, 855, 866, 877 or 888 number generally cannot be reached from outside the NANP at all, and the same is true of most countries' freephone and premium ranges — which is why companies publish a separate, ordinary geographic number for international callers. Mobile numbering also varies more than people expect: some countries reserve distinct prefixes for mobiles, and Argentina still requires a 9 inserted after the country code with the domestic 15 removed.
Two closing cautions. Calling-line display can be forged, so a call that shows a familiar country code proves nothing about where it came from, and an unexpected missed call from an unfamiliar code is a well-established premium-rate scam that pays out when you call back. And this page is a reference, not a dialer or a validator: it does not place calls, does not check whether a number is in service, and cannot see a numbering-plan change that happened after it was written. Anything that has to work first time is worth confirming with the person you are calling.
Questions people ask
What does the + actually do?
It stands for "whatever this country uses to dial out". A mobile network substitutes the local exit code automatically, so +44 20 7946 0958 connects from the US, Germany, Japan or anywhere else with no edits. Landlines have no + key, so on those you dial the real exit code — 011 in the US and Canada, 00 across most of the rest of the world. Store every international contact with the plus and the problem disappears permanently.
Do I always drop the leading zero?
Nearly always, and there are named exceptions. Italy keeps the leading 0 as part of the number. Russia, Kazakhstan and Lithuania use 8 rather than 0 as the trunk prefix, so that is the digit you drop. Hungary uses 06, so two digits go. And a fair number of countries have no trunk prefix at all, in which case there is nothing to remove. The lookup on this page states which case applies to the country you searched for.
Why does the same country code cover several countries?
Because a numbering plan can be shared. The North American Numbering Plan puts the US, Canada and around twenty Caribbean and Pacific territories inside +1, distinguished by area code, and Russia shares +7 with Kazakhstan. Sharing a country code says nothing about cost: several +1 Caribbean area codes are billed as international or premium calls from US carriers even though the number looks like a domestic one.
How current is this list?
It was compiled by hand and is accurate to the best of the author's knowledge at the time of writing, but numbering plans change: prefixes are reformed, codes are reassigned, and territories are added. The page is a quick reference for the common cases and it flags the countries known to behave unusually. It cannot dial, cannot validate a number, and should not be the last word on a call that matters — confirm the format with the recipient or your carrier.