磁链，是一个电磁学的物理量，为通电线圈的匝数与磁通量的乘积。通常用 (lambda)或 (psi)标记，即Ψ＝Nφ 或λ＝Nφ。其国际单位制单位与磁通量同为韦伯。

由于法拉第对电磁学的解释，一个线圈的磁链也可以表示为通过线圈的电压对其时间的积分。即：

因此其单位也可以用伏特·秒表示。

Flux linkage is a property of a two-terminal element. Although it is often confused with magnetic flux, the Flux linkage is actually an extension rather than an equivalent of magnetic flux. Flux linkage is defined as

where is the voltage across the device or the potential difference between the two terminals. This definition can also be written in differential form as