See the related link.
Here is a list of all telephone area codes ("claves LADA") in Mexico, from the Mexican government: http://www.sre.gob.mx/austin/Util/LadasMexico.html (The column labeled "clave actual" is the current area code. The telephone country code for Mexico is +52, and you must also insert the prefix '1' between the country code and the area code when calling a mobile phone or cell phone.)
In the UK, area code 020 is London, but there are no numbers beginning with 020 2. Other countries may have similar telephone area codes.
Look in the local telephone directory.
An area code finder is most commonly found in the white pages of a telephone book. Other places to find an area code finder would be at the local library or at the county clerk's office.
If you look at maps, you will not find area codes. Area codes can be found on area code locator websites. Another place to find area codes is in the telephone directory.
234 is the international country code for Nigeria - however - I can't find any reference to an area code starting 81 !
Chesterfield is in area code 636. Look in a telephone directory, either the printed kind or the online version.
get your postal code from here : http://find-postalcode.com/ and putting it in your account
The same local telephone number can exist in many different area codes. (After all, that's the whole point of area codes.) If you know where the telephone number is from, and if that place has only one area code, you can find out that way.
I can find no indication that the area code for Ghaziabad was ever 085. All current area codes beginning with 085 are in Andhra Pradesh, not Uttar Pradesh, halfway across the country. The area code for Ghaziabad is 0120.
If you need telephone service in an area you can use a google map search. You'd enter the city or zip code then select search nearby for "Telephone Service providers". If you were only interested in cell phone service you'd search for that instead.
Try countrycode.org. There, you can search for any country code that exists by name or number. If you try allareacodes.com you can get any area code within the United States and territories.