In general, it takes me about 190 watts (SRM power meter) to ride 20 mph on flat terrain - 6' tall 172 pounds but I am very optimized on position, helmet, clothes, tires, wheels, shaved legs and etc and about 285 to 300 watts to ride 25 mph on the same terrain. So if you can ride along at 25 mph at 300 watts +/- then the power meter is probably correct.