1. A method of estimating a volume of a remaining fluidum in a non-translucent recipient having an opening at a top side of the recipient which area of the opening is wider than or equal to the area of a bottom of the recipient, the method being implemented as an application program for an electronic device having a camera, said method comprising the steps of: taking a picture of the opening at the top side of the recipient by means of the camera; the electronic device: deriving from the picture characteristics of a first number of pixels representing a visible part of the recipient; deriving from the picture characteristics of a second number of pixels representing a visible part of the fluidum in the recipient; requesting from a user an identification of the recipient; receiving from the user the identification of the recipient; matching the received identification with a stored identification in order to retrieve reference data about an empty recipient; and estimating a volume of the remaining fluidum in the recipient by means of the retrieved reference data and a ratio of the characteristics of the first number of pixels and the characteristics of the second number of pixels, wherein the picture is taken from a first arbitrary angle to the recipient and from a first arbitrary distance to the recipient as long as the remaining fluidum and the recipient are visible for the camera, wherein a picture for creating the reference data is taken from a second arbitrary angle to the recipient and from a second arbitrary distance to the recipient as long as the remaining fluidum and the recipient are visible for the camera, and wherein the second arbitrary angle and the second arbitrary distance are independent from the first arbitrary angle and from the first arbitrary distance respectively.