Engineering / Browser calculator

Ohm's Law Calculator

Ohm's Law Calculator works from the inputs you provide and returns voltage (v), current (a), resistance (ω), power (w). Use the calculation panel to explore a scenario, then check the formula and limitations before applying the result.

Your inputs

Minimum: 0
Minimum: 0
Minimum: 0

Your results

Enter your values and calculate to see the result.

Estimates depend on the stated method and entered quantities. Check applicable standards before using a result for a real-world design or safety decision.

Formula and calculation method

V = IR. Power = VI. Use two known quantities to solve for the third.

Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.

How to use ohm's law calculator

  1. Set Solve for by choosing the option that matches your calculation.
  2. Set Voltage (V). The example below uses 12.
  3. Set Current (A). The example below uses 2.
  4. Set Resistance (Ω). The example below uses 6.
  5. Select Calculate to update the result. Reset restores the illustrated inputs. Copy, print or download your own result if you need a record.

Worked example

Example inputs
Solve for
Current
Voltage (V)
12
Current (A)
2
Resistance (Ω)
6
Voltage (V)
12
Current (A)
2
Resistance (Ω)
6
Power (W)
24

Factors affecting your result

Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.

Changing solve for changes the scenario being evaluated. Adjust one input at a time when comparing results, keep a copy of the assumptions, and compare values using the same unit and period. A precise arithmetic result does not make an uncertain assumption precise.

Frequently asked questions

How does the ohm's law calculator work?

V = IR. Power = VI. Use two known quantities to solve for the third.

What inputs does Ohm's Law Calculator need?

Enter solve for, voltage (v), current (a), resistance (ω). Choose values that correspond to the same situation and measurement convention.

How should I interpret the ohm's law calculator result?

Use consistent units for all comparable inputs. The displayed result is rounded; arithmetic is performed with the full available numeric precision. Check your source measurements before relying on the result.

Are my ohm's law calculator inputs uploaded?

No. The calculation runs in this browser. Favorites, recent tool names, theme and formatting preferences may be saved locally, but calculation inputs are not sent to a calculation server or stored by this website. Shared links do not include entered values.

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