Math & Science · Free online calculator
Ohm’s Law Calculator
Solve for voltage, current or resistance when the other two values are known.
CALCULATOR GUIDE
How the Ohm’s Law Calculator works
Solve for voltage, current or resistance when the other two values are known. This guide explains the inputs, calculation method, example and key limitations so you can check whether the result fits your question.
Solve for voltage, current or resistance when the other two values are known.
Ohm’s law: V = I × R; I = V ÷ R; R = V ÷ I.
Inputs to prepare
Before you calculate, gather the values the question asks for and check their units. Choose options carefully and use consistent dates, periods and starting values. The notes below describe the fields shown in the calculator above.
- CalculateChoose the option that matches your situation. Options include: Voltage, Current, Resistance
- Voltage (V)Use a numeric value and keep the displayed unit consistent. Allowed range: 0 to 1000000000
- Current (A)Use a numeric value and keep the displayed unit consistent. Allowed range: 0 to 1000000000
- Resistance (Ω)Use a numeric value and keep the displayed unit consistent. Allowed range: 0 to 1000000000
How to use the Ohm’s Law Calculator
- Enter the details. Fill in each required field and use the units or formats shown next to it.
- Check your assumptions. Confirm dates, comparison values, time periods and selected options before submitting.
- Calculate and review. Read the result together with its unit, time period and any additional breakdown.
- Compare scenarios. Change one input at a time if you want to understand how different values affect the outcome.
Formula and worked example
Ohm’s law: V = I × R; I = V ÷ R; R = V ÷ I.
Example calculation
2 amps through 6 ohms corresponds to 12 volts.
Try the same values in the calculator above. If your result differs, recheck the units, input order, assumptions and rounding displayed by the tool.
What your result means
Solve for voltage, current or resistance when the other two values are known. Read the result label and unit carefully. A useful estimate describes only the inputs and assumptions supplied; it should not be treated as proof of a future outcome or a guarantee.
- Check the displayed unit and period before comparing results.
- Use values from a reliable source and keep them up to date.
- Repeat the calculation with an independent check when the outcome matters.
Assumptions and limitations
Do not use the calculation as a wiring or electrical-safety procedure; physical circuits may have additional constraints.
The calculator is a general-purpose tool. Actual outcomes may depend on local rules, provider terms, measurement standards or personal circumstances not represented in the fields. For consequential financial, health, legal, tax or construction decisions, confirm the result with an appropriate authoritative or qualified source.
Frequently asked questions
How does the ohm’s law calculator work?
Ohm’s law: V = I × R; I = V ÷ R; R = V ÷ I.
Which inputs does the ohm’s law calculator use?
The fields shown above describe the inputs and units required for this method. Use consistent units and verify all values before calculating.
What should I check before using the ohm’s law calculator result?
Do not use the calculation as a wiring or electrical-safety procedure; physical circuits may have additional constraints.
For transparency, use the formula and worked example to check the output. Add authoritative references and have the calculation reviewed before relying on it for a consequential decision.