Do I need to register my drone?
If:


Your unmanned aircraft weighs between 250g and 25kg (including fuel and cargo),
You are not flying under the Special Rule for Model Aircraft, also known as section 336
You intend to operate it outdoors, and
You are operating it in the United States,


you need to register your drone through the FAA's online registration system.  If your drone is heavier than 25kg, you need to go through the regular aircraft registration process.  If your drone is ligher than 250g, or you are only operating it indoors, you do not need to register it.

Additionally, if you are operating the drone for commercial purposes, you must have a remote pilot airman certificate.

(Note: if you are younger than 13 years old, someone who is 13 or older needs to register your drone for you.)