There are a little over 180,000+ different dialling prefixes operated by the different telecoms operators in each of the 196 countries worldwide. These prefixes are then grouped into 1400+ separate charging tariffs across the world. That means that on average each country has 7 different rates for the different numbers you dial.
In reality, some just have Landline or Mobile and some have 50+ price groups and 1000's of prefixes. The UK is a good example, there are actually 259 different rate groups that a phone number could incur by the time you look at all premium rate numbers, expensive mobile networks like Lyca, 0845 charging, Directory Enquires etc. Equally, the USA occupies over 128,000 of the 180,000+ prefixes.
We set pricing for key destinations. In the UK we fix calls to 01, 02 and 03 as landline calls and equally we fix costs to mobiles for all the major mobile networks. We do the same for over 30 international destinations as shown on our Call Pricing page, but its clearly important you know the type of number you are dialing.
If you don't know the provider or type of the number you are calling (tough to know with international calls in particular) then we highly recommend using our call cost checker also found on our Call Pricing page. You just enter the number including the International Dialling prefix, such as +1 for USA numbers and it will give you a definitive cost of the call.