Physics

Ohms Law Calculator

Solve voltage, current, or resistance and compute electrical power.

Last validated: 2026-02-14

Use this free online Ohms Law Calculator to solve voltage, current, resistance, or power from basic circuit relations. It is useful for classwork, lab checks, design screening, and engineering sanity checks where units and assumptions must stay visible. The form focuses on Mode, Voltage (V), Current (A), Resistance (Ohm) and returns Ohm's Law Inputs, Result, so you can move from input to answer without setting up a spreadsheet or custom script. Run one realistic example, adjust the inputs, and compare how the result changes before you copy or share it. Check units and formula assumptions carefully; for safety-critical or code-governed work, validate the result with authoritative references.

Permalink

Input Pattern

Enter values in the left panel, keep units explicit, run the calculation, then copy or share the result. Invalid fields are highlighted immediately.

Ohm's Law Inputs

Use V = I * R and power P = V * I.

Result

Solved value: 12.000000

Power: 24.000000 W

How to use this tool

Enter Mode, Voltage (V), Current (A), Resistance (Ohm) for the ohms law calculator, keeping units, dates, or text format consistent with the form labels.
Choose the relevant mode, unit, or option values before running so the output answers the right version of the question.
Click "Run the tool" and review Ohm's Law Inputs, Result for the primary output.
Verify units and assumptions, especially before using the result for design, lab, or safety-sensitive work.

Worked Example

Auto-generated from the tool's current default or entered inputs.

Example Inputs

Mode: find_voltage
Voltage: 12.0
Current: 2.0
Resistance: 6.0
Power: 24.0

Expected Outputs

Voltage: 12
Current: 2
Resistance: 6
Result: 12

Interpretation

Voltage is 12.0. Use this as a decision input, not as a standalone conclusion.
Current is 2.0. Use this as a decision input, not as a standalone conclusion.
Resistance is 6.0. Use this as a decision input, not as a standalone conclusion.
Confirm unit consistency and operational constraints before applying this result in production or field conditions.

Confidence and limitations

Outputs are deterministic formula results and depend entirely on input quality and units.
Results are for planning and learning; verify with domain standards before safety-critical use.
Models are idealized and may ignore drag, friction, nonlinearity, and measurement error.

Formula References

SI-unit forms of classical mechanics and wave equations.
Idealized models unless explicitly stated otherwise.

Assumptions

Outputs are deterministic formula results and depend entirely on input quality and units.
Results are for planning and learning; verify with domain standards before safety-critical use.
Models are idealized and may ignore drag, friction, nonlinearity, and measurement error.

Explore more versions

Tailored guides for specific audiences, regions, and scenarios.

core

Electronics and circuit tools

Feature multimeters, electronics kits, and introductory circuit books.

Ohms Law Calculator

Input Pattern

Ohm's Law Inputs

Result

How to use this tool

Worked Example

Example Inputs

Expected Outputs

Interpretation

Confidence and limitations

Formula References

Assumptions

Explore more versions

Ohms Law Calculator

Ohms Law Calculator for Germany

Ohms Law Calculator for United Kingdom

Ohms Law Calculator for United States

Ohms Law Calculator for Students

Electronics and circuit tools