Discharge large orifice

$latex LARGE Q=frac{2}{3}cdot bcdot sqrt[2]{2gcdot left({h_{2}}^{frac{3}{2}}-{h_{1}}^{frac{3}{2}} right )}$     

b  = Width orifice              [m]
g  = Earths gravity= 9,81       [m/s²]
h₁ = Pressure at top orifice    [m]
h₂ = Pressure at bottom orifice [m]

Online spreadsheet, sometimes it won’t load, becuase it is a external program