How to Calculate Ohm's Law
What is Ohm's Law?
Ohm's Law states that the voltage across a conductor is proportional to the current flowing through it, with resistance as the proportionality constant: V = IR. Formulated by Georg Ohm in 1827, it is the most fundamental relationship in electrical engineering. It applies to ohmic materials at constant temperature; real-world components like diodes and transistors are non-ohmic.
Formula
- V
- voltage / current) — voltage / current)
- IR
- current × resistance) — current × resistance)
Step-by-Step Guide
- 1V = IR (voltage = current × resistance)
- 2I = V/R (current = voltage / resistance)
- 3R = V/I (resistance = voltage / current)
- 4Power: P = VI = I²R = V²/R
- 5Units: V (volts), A (amperes), Ω (ohms), W (watts)
Worked Examples
Frequently Asked Questions
What is Ohms Law?
Ohm's Law states that the voltage across a conductor is proportional to the current flowing through it, with resistance as the proportionality constant: V = IR. Formulated by Georg Ohm in 1827, it is the most fundamental relationship in electrical engineering
How accurate is the Ohms Law calculator?
The calculator uses the standard published formula for ohms law. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.
What units does the Ohms Law calculator use?
This calculator works with inches, watts. You can enter values in the units shown — the calculator handles all conversions internally.
What formula does the Ohms Law calculator use?
The core formula is: V = IR (voltage = current × resistance). Each step in the calculation is shown so you can verify the result manually.
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