An emergency telephone number is a number that allows a caller to contact local emergency services for assistance. The emergency number differs from country to country; it is typically a three-digit number so that it can be easily remembered and dialed quickly. Some countries have a different emergency number for each of the different emergency services; these often differ only by the last digit.
In many countries, dialing either 112 (used in Europe and parts of Asia, Africa and South America) or 911 (used mostly in the Americas) will connect callers to emergency services. For individual countries, see the list of emergency telephone numbers.