Method for determining a fill level of a dust container of a vacuum cleaner , the vacuum cleaner comprising: a first suction portion having a floor nozzle , a dust container , a second suction portion , a fan motor which is designed to generate a negative pressure, the floor nozzle , the first suction portion , the dust container , the second suction portion and the fan motor in this order forming a suction path and being fluidly coupled to one another in such a way that air can be and is sucked in by the fan motor through the floor nozzle into the first suction portion , the dust container and the second suction portion , the method comprising the following steps: - measuring at least one motor characteristic of the fan motor as a function of time, - determining a first parameter from the motor characteristic, the first parameter correlating with a volume flow and/or negative pressure in the second suction portion or being a volume flow or negative pressure in the second suction portion , - determining a second parameter, the second parameter correlating with a volume flow and/or negative pressure at the floor nozzle or being a volume flow or negative pressure at the floor nozzle , - determining a degree of filling of the dust container from the first parameter and the second parameter, characterised in that the second parameter is determined from the hydraulic resistance at the floor nozzle , a detected floor surface and the first parameter. a first suction portion having a floor nozzle , a dust container , a second suction portion , a fan motor which is designed to generate a negative pressure, the floor nozzle , the first suction portion , the dust container , the second suction portion and the fan motor in this order forming a suction path and being fluidly coupled to one another in such a way that air can be and is sucked in by the fan motor through the floor nozzle into the first suction portion , the dust container and the second suction portion , the method comprising the following steps: - measuring at least one motor characteristic of the fan motor as a function of time, - determining a first parameter from the motor characteristic, the first parameter correlating with a volume flow and/or negative pressure in the second suction portion or being a volume flow or negative pressure in the second suction portion , - determining a second parameter, the second parameter correlating with a volume flow and/or negative pressure at the floor nozzle or being a volume flow or negative pressure at the floor nozzle , - determining a degree of filling of the dust container from the first parameter and the second parameter, characterised in that the second parameter is determined from the hydraulic resistance at the floor nozzle , a detected floor surface and the first parameter. - measuring at least one motor characteristic of the fan motor as a function of time, - determining a first parameter from the motor characteristic, the first parameter correlating with a volume flow and/or negative pressure in the second suction portion or being a volume flow or negative pressure in the second suction portion , - determining a second parameter, the second parameter correlating with a volume flow and/or negative pressure at the floor nozzle or being a volume flow or negative pressure at the floor nozzle , - determining a degree of filling of the dust container from the first parameter and the second parameter, characterised in that the second parameter is determined from the hydraulic resistance at the floor nozzle , a detected floor surface and the first parameter. <EOS>