Apparent Power Calculator
Calculate apparent power (VA) from voltage and current, single or 3-phase.
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Introduction
Apparent Power Calculator — Calculate apparent power (VA) from voltage and current, single or 3-phase. Enter Voltage (V), Current (A), Phase to get an instant, accurate result.
Formula
Single-phase: S = V × I. Three-phase: S = √3 × V_line × I_line. Result is in volt-amps (VA).
Step-by-step
- Enter the Voltage (V).
- Enter the Current (A).
- Enter the Phase.
- Click Calculate to see your result instantly.
Real-world example
Example: With Voltage (V) = 120, Current (A) = 10, Phase = no, the Apparent Power Calculator gives Apparent Power Va: 1200, Three Phase: no.
Frequently Asked Questions
How is apparent power different from real power?
Apparent power (VA) is simply voltage times current; real power (W) is apparent power reduced by the power factor (W = VA × PF). They're equal only when power factor is exactly 1.
Why is apparent power used to size equipment like transformers?
Transformers, generators, and UPS units are current-limited regardless of power factor, so their capacity is rated in VA (apparent power) rather than W, since that reflects the actual current they must carry.
What inputs does the Apparent Power Calculator need?
You'll need to provide: Voltage (V), Current (A), Phase. All fields use sensible defaults, so you can see a working example immediately and then adjust the values to match your own numbers.
How accurate is the Apparent Power Calculator?
The Apparent Power Calculator applies the formula exactly as calculated — Single-phase: S = V × I. Three-phase: S = √3 × V_line × I_line. Result is in volt-amps (VA). — so results are precise for the inputs you provide. Accuracy depends on entering correct, realistic input values.
Is the Apparent Power Calculator free to use?
Yes, the Apparent Power Calculator is completely free, requires no signup, and runs instantly in your browser.
About the Apparent Power Calculator
The Apparent Power Calculator uses a real, verifiable formula — Single-phase: S = V × I. Three-phase: S = √3 × V_line × I_line. Result is in volt-amps (VA). — so results are accurate every time, not an approximation.