What is the US phone code?

The telephone country code for the United States (plus Canada and certain Caribbean and nearby islands) is +1.

The prefix for an outbound international call from the US (other than to Canada and the aforementioned islands) is 011.

(The plus sign means "insert your international access prefix here." From a GSM mobile phone, you can enter the number in full international format, starting with the plus sign. The most common prefix is 00, but North America (USA, Canada, etc.) uses 011, Japan uses 010, Australia uses 0011, and many other countries use different prefixes.)