A self-calibrating system, apparatus, and method for accurately measuring a volumetric capacity of a tank. The system, apparatus and method comprise: a mechanism that adjusts a level of a platform; a light-emitting device with beam-like optics (laser, diode, etc.) mounted to the platform; mechanism for adjusting alignment of the light-emitting device with respect to the platform; a mechanism for rotating the platform by variable angles, including by 180-degrees; one or more level sensors (such as, for example, spirit levels, tilt sensors, or other devices) that provide feedback on the alignment of the platform normal to the gravity vector.