TV station powers are listed as Effective Radiated Power (ERP) in Watts. Usually, the aural ERP is one-tenth the visual. Almost all of the notes related to VHF-FM stations apply to TV stations as well. We show both horizontal and vertical ERP; almost all TV stations in North America are horizontally-polarized. Those that aren't are usually circularly polarized. Some TV stations are elliptically polarized; unfortunately, the FCC's TV engineering database does not contain the precise vertical ERP component for those stations, so in our listings elliptical and circular stations are shown identically.
The maximum licensed power for a VHF low-band (channels 2 to 6) station is 100 kW; for VHF high-band (channels 7 to 13), 316 kW (325 kW in Canada). For UHF stations more than 100 km from the Canadian border, the maximum power is 5000 kW; UHF stations within 100 km of the Canadian border are restricted to 1000 kW, unless grandfathered. In all cases, the actual power limit for a specific site depends on the height of the antenna, and contour overlap with other stations.
There are different rules and maxima for digital TV stations. Most significantly, DTV stations are licensed on the basis of average power, as opposed to peak power which is used for analog stations. It is commonly assumed that a DTV station has a service area equivalent to an analog station with peak power five times the digital station's average power.