Magnetic Flux Conversion Calculator
Written by Thierno Sadou Diallo, formula verified per our methodology • Last checked on 9/10/2026
Magnetic flux converts between weber and maxwell with the exact factor 10⁸: 1 weber equals 100 million maxwells. A flux of 0.0005 weber therefore corresponds to 50,000 maxwells.
Explanation
Magnetic flux measures the total amount of magnetic field passing through a given surface, and is expressed in two unit systems depending on context: the weber (Wb), the SI unit derived from the volt-second, and the maxwell (Mx), an older CGS (centimeter-gram-second) unit still found in the technical documentation of some older electromagnetic equipment, notably in the United States. The relationship between the two (1 Wb = 10⁸ Mx exactly) follows directly from the respective definitions of the SI and CGS systems for electromagnetic quantities, with no physical measurement involved — a pure conversion factor, similar in principle to the relationship between the magnetic field in tesla and gauss, the other electromagnetic quantity where an SI unit and an inherited CGS unit coexist. Since the factor 10⁸ is very large, a typical value in weber (often on the order of a milliweber or less for most common electrotechnical applications) corresponds to a much larger number in maxwells.
Example: converting 0.0005 weber to maxwells
Inputs
Value: 0.0005. Starting unit: weber. Target unit: maxwell.
Calculation
0.0005 Wb × 10⁸ = 50,000 Mx.
Result
A magnetic flux of 0.0005 weber equals 50,000 maxwells.
Frequently asked questions
Why is the maxwell still used when the weber is the official unit?
The maxwell remains present in the technical documentation of some older equipment or equipment made to historical North American standards, as well as in certain specialized fields (materials magnetism, fundamental physics research) where CGS-unit orders of magnitude remain established practice. The weber nonetheless remains the legal SI unit, used in modern teaching and electrical engineering.
What is the difference between magnetic flux and magnetic field?
The magnetic field (measured in teslas) describes the local intensity of magnetism at a point in space, while the magnetic flux (measured in webers) measures the total amount of that field passing through a given surface — the flux therefore depends on both the field and the size of the surface considered, exactly as a water flow rate depends on both the current speed and the pipe cross-section.
How do you calculate a magnetic flux from a field and a surface?
That is a different calculation from this unit conversion: you multiply the magnetic field (in teslas) by the area of the surface crossed (in m²) and by the cosine of the angle between the field and the surface normal. Our dedicated magnetic flux calculator performs that calculation directly, before any conversion to the maxwell is needed.