A bubble level (100, 100', 200, 300, 400, 500) for calculating the position of a gas bubble, said bubble level (100, 100', 200, 300, 400, 500) comprising a cylindrically shaped sealed housing having an inner bottom surface, said sealed housing being partially filled with liquid and containing said gas bubble, the bubble level (100, 100', 200, 300, 400, 500) further comprising: at least two light-emitting devices (D1 - DM, 508), said light-emitting devices (D1-DM, 508) being configured to illuminate said gas bubble and said inner bottom surface of said sealed housing; and at least two light receiving devices (Q1 - QN, 508), each light receiving device (Q1 - QN, 508) being configured to receive light that is reflected by said inner bottom surface, and reflected or refracted by said gas bubble and configured to convert the received light into electrical signals; and a processing unit that is configured to process said electrical signals from the receiving devices so as to calculate the position of the said gas bubble, characterized in that, each of said at least two light-emitting devices (D1 - DM, 508) and each of said at least two light receiving devices (Q1 - QN, 508) are alternately arranged around the periphery of said cylindrically shaped sealed housing, and in that the processing unit is configured to record a signal from each of the light receiving devices upon illumination by each of the light-emitting devices, respectively, so as to obtain M*N signals Uij after each of the light-emitting devices have been illuminated once, wherein i=1 to M, j=1 to N, M being the number of light-emitting devices, N being the number of light receiving devices, and wherein the processing unit is further configured to calculate the position of the gas bubble based on the signals Uij. at least two light-emitting devices (D1 - DM, 508), said light-emitting devices (D1-DM, 508) being configured to illuminate said gas bubble and said inner bottom surface of said sealed housing; and at least two light receiving devices (Q1 - QN, 508), each light receiving device (Q1 - QN, 508) being configured to receive light that is reflected by said inner bottom surface, and reflected or refracted by said gas bubble and configured to convert the received light into electrical signals; and a processing unit that is configured to process said electrical signals from the receiving devices so as to calculate the position of the said gas bubble, characterized in that, each of said at least two light-emitting devices (D1 - DM, 508) and each of said at least two light receiving devices (Q1 - QN, 508) are alternately arranged around the periphery of said cylindrically shaped sealed housing, and in that the processing unit is configured to record a signal from each of the light receiving devices upon illumination by each of the light-emitting devices, respectively, so as to obtain M*N signals Uij after each of the light-emitting devices have been illuminated once, wherein i=1 to M, j=1 to N, M being the number of light-emitting devices, N being the number of light receiving devices, and wherein the processing unit is further configured to calculate the position of the gas bubble based on the signals Uij.