In a method for monitoring a radio-frequency power amplifier, and a radio-frequency device, and a radio-frequency monitoring device and a magnetic resonance tomography system, radio-frequency pulses are emitted at temporal intervals by the radio-frequency power amplifier, and measurement values that represent the power of the radio-frequency pulses are measured at temporal intervals. The measurement values are respectively loaded with a measurement error. Control values are respectively formed based on the sum of a number of measurement values loaded with measurement errors, and the radio-frequency power amplifier is limited in operation if and when a control value reaches or exceeds a predetermined limit control value.