Ohm's Law Calculator

Solve for Voltage, Current, Resistance, or Power using any two known variables with interactive wheel selectors and dynamic circuit schematic updates.

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Ohm's Interactive Wheel

Select the parameters quadrant you wish to solve for on the vector wheel. Inputs customize automatically.

V = Voltage (V)I = Current (A)R = Resistance (Ω)P = Power (W)

Current (I)

Resistance (R)

Calculated Voltage (V)

12.0000 V

Formula Trace: V = I × R = 2 A × 6 Ω

📊 Dashboard values

Voltage12.0000 V

Current2.0000 A

Resistance6.0000 Ω

Power24.0000 W

Dynamic Circuit Schematic

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Ohm's Law Guide

Ohm's Law maps the elementary relationship governing electron flow potential, currents, and load resistance in electric circuits.

The formula structure relates standard metrics:

Voltage ($V$): Potential difference that pushes charged electrons through loops. Measured in Volts ($V$).
Current ($I$): Rate of charge passing a point. Measured in Amperes ($A$).
Resistance ($R$): Opposing force to standard currents. Measured in Ohms ($\Omega$).
Power ($P$): Energy transmission velocity metric standard. Measured in Watts ($W$).

Common FAQs

How is SI unit prefix scaling processed?

SI metrics are parsed dynamically to standard base values before computing results. This ensures prefixes like milli (m) or micro (μ) are scaled correctly to base Ohms or Amperes.

What does the dynamic circuit diagram visualize?

The diagram maps battery terminals representing Voltage potential ($V$), standard resistors representing load ($Omega$), and current loops ($A$) to provide a real-world perspective.

Can I solve for any two known inputs?

Yes! Simply toggle the variable you want to find. The input fields will dynamically customize to ask for the other two known variables.

V = IR and the Power Wheel

The four quantities, any two given

Ohm's law plus the power formulas connect V, I, R and P — know two, get all four:

Want	From V and I	From V and R	From I and R
Resistance R	V ÷ I	—	—
Current I	P ÷ V	V ÷ R	—
Voltage V	P ÷ I	—	I × R
Power P	V × I	V² ÷ R	I² × R

Household math that pays for itself

On Pakistan's 220 V mains, P = VI turns appliance labels into bills: a 2000 W heater draws about 9 A (so a 6 A-rated extension lead is a fire hazard for it), and running it three hours daily is 180 kWh a month — multiply by your tariff slab and the heater's real cost appears. UPS sizing works the same way backwards: total the wattage you must keep running, add headroom, and the battery/inverter spec follows.

Limits and neighbors

Ohm's law is exact for resistive loads; motors and electronics complicate things with power factors — for homework and household estimation the simple form serves. The arithmetic around tariffs and units runs in the percentage calculator and scientific calculator, and other formula-triangle physics (ρ = m/V) lives in the density calculator.