Hello Happy girl,
I suppose the reason why there isn’t such a website is because, in order for such an application to work, one would need to enter a phone number in its standardized international format (beginning with the country code). Those who find it difficult to identify a phone number’s country of origin would likely enter whatever digits they have, often without the country code. In this case the application would not be able to identify the country, or would point to the wrong one.
In short, even though there might be such an application, especially a smart phone app, it would not always work.
If you have a complete phone number you can easily identify its country by checking a country code list. Our home page for instance has a feature titled “Reverse country code lookup” where you can choose a country code and see what country it belongs to, along with additional information about that specific country’s phone numbers (number of digits, phone number type and so on).
If you have an incomplete number (no country code) identifying the country is rarely possible.