A method for operating an internal combustion engine in which fresh air, under ambient pressure, is compressed with the aid of a compressor, in particular an exhaust gas turbocharger, and supplied to a combustion chamber of the internal combustion engine via a throttle device, the rotational speed of the compressor being ascertained with the aid of a sensor, in particular a pressure sensor, the rotational speed of the compressor being used for determining the ambient pressure or a boost pressure applied downstream from the compressor and upstream from the throttle device.