Field Strength Estimator is a free Android application developed by Rohde & Schwarz GmbH & Co. KG under the category of Business & Productivity. It is a powerful tool that calculates power flux density, electric and magnetic field strength from the transmitted power, associated frequency, and gain of the transmitting antenna. The program also calculates the input power into a receiver with a 50 Ohm input impedance from the gain of the receiving antenna.

The program automatically converts power flux density into electric and magnetic field strength. It is important to note that the program does not consider impairments such as non-line-of-sight propagation, changes in polarization, reflections, multi-path propagation, antenna VSWR, and cable losses. Therefore, the program is classified as an estimator and not a calculator.

The program is easy to use and requires the user to select a row by touching it and change a specific value. Upon touching the "Estimator" button, the dependent values are calculated automatically. The results are displayed with three decimal places only (except for the antenna gain values, which are displayed with one decimal place). The application is based on the application note "1MA85: Field Strength and Power Estimator" by Rohde & Schwarz GmbH & Co. KG.