Capacitance type fuel quantity indicators can provide the mass of the fuel, in opposition with other fuel gauging systems that may give only the volume. The problem with the volume-based instruments is that they are subject to temperature variations. If the temperature decreases, the density will increase, and fuel volume will decrease, which will give a false indication about the actual usable fuel within the tanks.

In a capacitance system, the insulating material between the two plates is called dielectric. In this case, the dielectric is a mixing of fuel and air. In simple terms, the dielectric permittivity represents the ability of electrical charges to propagate through the dielectric. Fuel has approximately twice the capacitance of the air, but it will change as density changes. This will also influence the dielectric permittivity as an increase in density due to a lower temperature will cause an increase the dielectric permittivity.