EngiRef / Electromagnetic Constant

Vacuum Permeability

Vacuum Permeability (μ₀) = 1.2566 × 10^-6 H/m. Magnetic constant. Since the 2019 SI redefinition μ₀ is a measured quantity; 4π × 10⁻⁷ H/m is the pre-2019 exact…

electromagneticμ₀

Specification

Name
Vacuum Permeability
Symbol
μ₀
Value
1.2566 × 10^-6
Unit
H/m
Category
electromagnetic
Description
Magnetic constant. Since the 2019 SI redefinition μ₀ is a measured quantity; 4π × 10⁻⁷ H/m is the pre-2019 exact value and now differs in the 10th digit.