Use the formula (V = frac{W}{Q})
Identify the work done (W) in joules
Identify the charge (Q) in coulombs
Divide work done by charge
Use Ohm’s law if current and resistance are known: (V = IR)
Identify the current (I) in amperes
Identify the resistance (R) in ohms
Multiply current by resistance
Measure with a voltmeter connected in parallel across the two points
Read the voltage value directly from the voltmeter