Magnetic permeability converter
Convert a material’s magnetic permeability between μr, H/m and susceptibility.
That's about the same as electrical steel.
What it means
How strongly does it gather field?
Figures for iron and alloys are typical maximum or initial values. Real permeability changes with field strength, frequency and temperature.
Every unit
Your permeability in every unit
Learn
Three things worth knowing
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A vacuum is 1.2566 μH/m
Multiply μr by 1.2566 μH/m for absolute permeability. Electrical steel at 4,000 is about 5 mH/m.
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Fixed, then measured
Until 2019 the vacuum permeability was exactly 4π × 10⁻⁷ H/m by definition. Since the SI redefinition it is measured, and agrees with that value to ten decimal places.
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Most things are not magnetic
Water, wood and people have μr within a hundred-thousandth of 1. Water is even slightly below 1: it is weakly pushed away by a strong magnet.
Shortcuts
Popular magnetic permeability conversions
Background
About magnetic permeability
Permeability says how readily a material carries magnetic field lines. Relative to a vacuum it is μr: almost exactly 1 for air, water and aluminum, thousands for electrical steel.
High permeability is what lets a transformer core channel the field from one coil to the other, and what lets a mu-metal box shield a sensitive instrument.