The dimensional formula for magnetic flux is:

Dimension of magnetic flux = Dimension of voltage $\times$ Dimension of time 

$\begin{array}{l}=\left[{\mathrm{ML}}^2{\mathrm{T}}^{-3}{\mathrm{A}}^{-1}\right]\left[\mathrm{T}\right]=\left[{\mathrm{ML}}^2{\mathrm{T}}^{-2}{\mathrm{A}}^{-1}\right]\\ \because \text{ Voltage }=\frac{\text{ work }}{\text{ charge }}\end{array}$