This information has been summarized and reduced in order to provide a basic understanding; exceptions are not fully covered. Please always refer to current FARs to get all necessary details.
FAR 61.123 [Eligibility Requirements] [Excerpt]
To be eligible for a commercial pilot certificate, you must:
1. Be at least 18 years of age.
2. Be able to read, speak, write and understand the English language.
3. Hold at least a private pilot certificate.
4. Meet the aeronautical experience requirements of this section that apply to the aircraft category and class rating sought.
5. Pass the knowledge test.
6. Pass the practical test.
To exercise the privileges of a commercial pilot certificate, you must hold at least a current second-class medical certificate.
FAR 61.125 [Aeronautical Knowledge] [Excerpt]
If you are applying for a commercial pilot certificate you must receive and log ground training from an authorized instructor or complete a home-study course on the aeronautical knowledge areas of this section that apply to the aircraft category and class rating sought.
If you are applying for a commercial pilot certificate with an airplane category and single engine class rating, you must log at least 250 hours of flight time as a pilot (of which 50 hours, or in accordance with FAA Part 142, a maximum of 100 hours may have been accomplished in an approved flight simulator or approved flight training device that represents a single engine airplane) that consists of at least:
1. 100 hours in powered aircraft, of which 50 hours must be in airplanes.
2. 100 hours of pilot in command flight time, which includes at least 50 hours in airplanes and 50 hours in cross-country flight in airplanes.
3. 20 hours of training on the areas of operation as listed for this rating, that includes at least 10 hours of instrument training, of which at least 5 hours must be in a single engine airplane, 10 hours of training in an airplane that has a retractable landing gear, flaps, and a controllable pitch propeller, or is turbine-powered, one cross- country flight of at least 2 hours in a single engine airplane in day VFR conditions, consisting of a total straight-line distance of more than 100 nautical miles from the original point of departure, one cross-country flight of at least 2 hours in a single engine airplane in night VFR conditions, consisting of a total straight-line distance of more than 100 nautical miles from the original point of departure.
4. 10 hours of solo flight in a single engine airplane, including one cross-country flight of not less than 300 nautical miles total distance and as specified, and 5 hours in night VFR conditions with 10 takeoffs and 10 landings (with each landing involving a flight in the traffic pattern) at an airport with an operating control tower.