How to find Horsepower when ampere in known?

How to find Horsepower when ampere in known?
Horsepower = Engine Output Power.
Ampere = Input Current

Examples :
If given Ampere(I) = 5A ; Volt(V) = 240V ,
then, (I) x (V) = Watts(W),
is 5A x 240V = 1200W,
Next multiply watts by 0.00134 (1/746)and you will have horsepower.
1200W x 0.00134 = 1.608HP

So, basically the formula to get the horsepower are:
HP = (V) x (I) x (1/746),
More accurate is HP = [(V) x (I) x %eff x pf] x (1/746).

For 3 Phase Horsepower,
HP = [(V) x (I) x %eff x 1.73 x pf] x (1/746).

Where %eff = efficiency of the motor and pf = power factor..

Electrical :- Horsepower (Hp)

Electrical input power = Input voltage x Input current, where P = VI ...

Relations between HP(Horsepower) & Kw(Kilowatt)

hp = kW
1.0 = 0.735(0.75)
2.0 = 1.471(1.5)
3.0 = 2.206(2.25)
4.0 = 2.942(3.0)
5.0 = 3.677(3.75)
6.0 = 4.413(4.5)
7.0 = 5.148(5.25)
8.0 = 5.884
9.0 = 6.619