Abstract: A device for measuring and calibrating the strength of magnetic fields is provided. The device includes a coil of wire and either conductive pads or an ammeter/voltmeter attached to the coil of wire. The coil is disposed in the interior of a housing, and a locator window is formed in the housing in a position internal to the coil. The locator window allows the user to see through the device and thus position the device properly with respect to the source of the magnetic field. Preferably, a microprocessor is provided which converts a value of voltage or current induced in the coil into a value of magnetic field strength. The microprocessor transmits the value of magnetic field strength to the display.