Flow measuring device having a first and a second flow measuring transducer operating on different operating principles for improved measurement accuracy

A method for determining a flowed amount of a medium includes using a first flow measuring transducer according to a first measuring principle and a second flow measuring transducer according to a second measuring principle. The measured values of the first transducer are more reliable in first states of the medium than measured values of the second transducer, and the second measured values are more reliable in second states than the first measured values. A contribution to the flowed amount is ascertained based on the more reliable measured values. The contribution to the flowed amount based on the second measured values is ascertained via a transfer function. An updated version of the transfer function is ascertained when the first measured values are more reliable, and the flowed amount earlier ascertained based on the second measured values is corrected as a function of the updated transfer function.