Online Current, Voltage & Power Calculator

Enter any two known values and click calculate to get the third.

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Formula Reference
电功率计算公式: \(P = V \times I\)
P
Calc Power
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Current Voltage
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Power
I
Calc Current
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Power Voltage
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Current
V
Calc Voltage
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Power Current
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Voltage

Online Power Calculator Guide

This online calculator helps you quickly compute Current (I), Voltage (V), and Power (P). Simply enter any two known values, and the tool will automatically calculate the remaining one using standard electrical formulas.

The power formula P = V × I is fundamental in circuit analysis. It explains how voltage and current determine energy consumption and helps estimate device power usage accurately.

Ohm’s Law is the foundation of this calculator, describing the relationship between voltage, current, and resistance. This tool is useful for LED circuits, battery life estimation, and component protection.

With a clean and easy-to-use interface, this calculator delivers fast and accurate results, clearly displaying values and units to improve efficiency in electrical design and troubleshooting.

Quiz: Test Your Knowledge

1. What is voltage?

Voltage is the electrical potential difference that drives electric charge flow.

2. What is the formula for electric power?

Power (P) = Voltage (V) × Current (I)

3. What is the unit of current?

The unit of current is the ampere (A).

4. What is the formula of Ohm’s Law?

Voltage (V) = Current (I) × Resistance (R)

5. What is the unit of resistance?

The unit of resistance is the ohm (Ω).

6. How do you calculate voltage from power and current?

Voltage (V) = Power (P) ÷ Current (I)

7. How do you calculate current from power and voltage?

Current (I) = Power (P) ÷ Voltage (V)

8. What is the unit of electrical energy consumption?

Electrical energy is commonly measured in watt-hours (Wh) or kilowatt-hours (kWh).

9. How do you calculate total resistance in series?

Total resistance equals the sum of all resistors (R1 + R2 + ... + Rn).

10. How do you calculate total resistance in parallel?

1 ÷ Total resistance = 1 ÷ R1 + 1 ÷ R2 + ... + 1 ÷ Rn

Current · Voltage · Power Calculator

Quickly calculate current, voltage, and power for study, design, and electrical work.

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