The SI unit of magnetic flux is the weber, named after German physicist Wilhelm Eduard Weber.
Magnetic flux describes the total magnetic field passing through a specified surface. One weber is the amount of flux that, when reduced uniformly to zero through a one-turn circuit in one second, induces an electromotive force of one volt. This definition connects flux with electromagnetic induction.
The weber is related to the tesla, the SI unit of magnetic flux density. One weber equals one tesla multiplied by one square metre. Flux therefore depends both on field strength and on the area and orientation of the surface being considered.
Wilhelm Weber worked on magnetism, electrical measurements, and precision instruments during the nineteenth century. A common confusion is treating flux and flux density as identical: flux is measured in webers, whereas flux density is measured in teslas.