# Back EMF Online Calculator and How it is Calculated

`$V_{bemf} = (I_s - I_n) * R$`

, where

`$I_n = \frac{V_s}{R}$`

is the no load current, where `$V_s$`

is source voltage,

`$R$`

is the winding resistance,

`$I_s$`

is the stall current

`$V_{bemf} = (I_s - I_n) * R$`

, where

`$I_n = \frac{V_s}{R}$`

is the no load current, where `$V_s$`

is source voltage,

`$R$`

is the winding resistance,

`$I_s$`

is the stall current