How can i calculate voltage drop in a parallel circuit?

In a parallel circuit, the voltage across two components in parallel are identical and equivalent, although the currents flowing through them is different as it is determined by the resistance of each branch, in accordance with Ohms Law. ##V=I*R##.

You can calculate this by the formula above, measuring the current flowing in each branch, and measuring the resistance of each branch, and applying Ohms law to obtain the voltage drop across the circuit.