Ohm’s Law: Voltage, Current, Resistance and Power
Solve an ideal resistor from six explicit pairs of voltage, current, resistance or power; handle zero-load and indeterminate inputs accurately.
Use this result well
- Inputs that matter
- Voltage magnitude (V), Current magnitude (A), Sources and assumptions, Resistance (ohm), and 1 more
- Output to expect
- Voltage magnitude (V) + Current magnitude (A), Voltage magnitude (V) + Resistance (ohm), Current magnitude (A) + Resistance (ohm), Voltage magnitude (V) + Power (W), and 2 more
- Check the units and required inputs before comparing results.
- Keep the assumptions with a copied result so you can reproduce the calculation later.
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Reference & details
How it works
Updated September 2026
How it works
Updated September 2026Voltage magnitude (V) + Current magnitude (A)
Solve an ideal passive, finite positive resistance from exactly two selected magnitudes. A zero voltage/current or voltage/power pair cannot determine resistance uniquely. This model excludes reactive impedance and signed circuit direction.
V = I × R; P = V × I = I² × R = V² / R.Voltage magnitude (V) + Resistance (ohm)
Solve an ideal passive, finite positive resistance from exactly two selected magnitudes. A zero voltage/current or voltage/power pair cannot determine resistance uniquely. This model excludes reactive impedance and signed circuit direction.
V = I × R; P = V × I = I² × R = V² / R.Current magnitude (A) + Resistance (ohm)
Solve an ideal passive, finite positive resistance from exactly two selected magnitudes. A zero voltage/current or voltage/power pair cannot determine resistance uniquely. This model excludes reactive impedance and signed circuit direction.
V = I × R; P = V × I = I² × R = V² / R.Voltage magnitude (V) + Power (W)
Solve an ideal passive, finite positive resistance from exactly two selected magnitudes. A zero voltage/current or voltage/power pair cannot determine resistance uniquely. This model excludes reactive impedance and signed circuit direction.
V = I × R; P = V × I = I² × R = V² / R.Current magnitude (A) + Power (W)
Solve an ideal passive, finite positive resistance from exactly two selected magnitudes. A zero voltage/current or voltage/power pair cannot determine resistance uniquely. This model excludes reactive impedance and signed circuit direction.
V = I × R; P = V × I = I² × R = V² / R.Resistance (ohm) + Power (W)
Solve an ideal passive, finite positive resistance from exactly two selected magnitudes. A zero voltage/current or voltage/power pair cannot determine resistance uniquely. This model excludes reactive impedance and signed circuit direction.
V = I × R; P = V × I = I² × R = V² / R.Updated: September 2026
Example Scenarios
Try this example to see the calculation, then enter actual documented values and preserve the measurement conditions. A failed or unresolved comparison is part of the record.
→ 10 V · 0.1 A
Try this example to see the calculation, then enter actual documented values and preserve the measurement conditions. A failed or unresolved comparison is part of the record.
→ 10 V · 0.1 A
Try this example to see the calculation, then enter actual documented values and preserve the measurement conditions. A failed or unresolved comparison is part of the record.
→ 10 V · 0.1 A
Try this example to see the calculation, then enter actual documented values and preserve the measurement conditions. A failed or unresolved comparison is part of the record.
→ 10 V · 0.1 A
Try this example to see the calculation, then enter actual documented values and preserve the measurement conditions. A failed or unresolved comparison is part of the record.
→ 10 V · 0.1 A
Try this example to see the calculation, then enter actual documented values and preserve the measurement conditions. A failed or unresolved comparison is part of the record.
→ 10 V · 0.1 A
FAQ
About Ohm’s Law: Voltage, Current, Resistance and Power
Solve an ideal passive, finite positive resistance from exactly two selected magnitudes. A zero voltage/current or voltage/power pair cannot determine resistance uniquely. This model excludes reactive impedance and signed circuit direction.