A flow sensor (1) enables determination of a flow signal corresponding to a flow of a fluid of a fluid administration system. A housing (11) has arranged a flow input (1 i), a flow chamber (1 2) and a flow output (1o) being designed that the flow input (1i) and the flow output (1o) can be connected to the fluid administration system such that at least an amount of the fluid of the fluid administration system can consecutively pass the flow input (1i), the flow chamber (12) and the flow output (1o). The housing (11) has further arranged a first mechanical sensor (13) for recording a raw flow signal corresponding to the flow of the fluid passing the flow chamber (12) and an ambient noise. The housing (11) has further arranged a second mechanical sensor (14) for recording an ambient noise signal corresponding to the ambient noise. The housing (11) and the arrangement of the first mechanical sensor (13) and the arrangement of the second mechanical sensor (14) are designed that a signal processing unit (3) receiving the raw flow signal (3r) and the ambient noise signal (3a) is enabled to determine the flow signal (3f) from the raw flow signal (3r) and the ambient noise signal (3a) in such a manner that the flow signal (3f) exhibits less ambient noise than the raw flow signal (3r).
