What formula is used?
PF = W ÷ VA
Electrical planning tool
Power Factor Calculator
Calculate power factor from real power in watts and apparent power in volt-amperes.
Interactive calculator
Power Factor Calculator
Result
0.800 PF
PF = W ÷ VA
Live circuit diagram
Power Factor Calculator visualized in real time
Values update as you use the calculator.
Input
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Circuit setting
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Calculated output
Enter values to see the live result
Quick answers
Power Factor Calculator: quick answers
Get concise answers to the most common power factor calculator questions before reviewing the formulas, examples, and detailed guidance below.
Can I use decimal inputs?
Yes, enter positive decimal values.
How accurate is the result?
The arithmetic follows the formula; practical accuracy depends on input quality and assumptions.
Formula
Power factor formulas
Choose the formula that matches the electrical system and known values.
Primary formula
PF = W ÷ VA
Use consistent input units.
Related formula
W = VA × PF
Rearrange the same relationship.
Verification
Check inputs and assumptions
Practical systems may require additional factors.
How to use
Calculate in five clear steps
Check every unit and use measured or nameplate values where possible.
- 1. Identify the values required by the formula.
- 2. Enter positive values in the displayed units.
- 3. Review the instant result.
- 4. Compare with a worked example.
- 5. Verify final decisions using bills, measurements, ratings, or codes.
Worked examples
Practical calculation examples
Examples make the formula and its assumptions easier to verify.
800 W and 1,000 VA
0.80 PF
900 W and 1,000 VA
0.90 PF
1,840 W and 2,300 VA
0.80 PF
4,500 W and 5,000 VA
0.90 PF
8,500 W and 10,000 VA
0.85 PF
950 W and 1,000 VA
0.95 PF
Accuracy
Common mistakes and limitations
The result is only as reliable as the selected formula and input data.
Conversion library
Explore all 44 electrical calculators
Continue from the Power Factor Calculator to a dedicated conversion tool for watts, amps, volts, kW, kVA, energy, batteries, or circuit calculations. Each linked page includes its own formula, examples, and guidance.
FAQ
Power factor questions
Direct answers to common calculation questions.
What formula is used?
PF = W ÷ VA
Can I use decimal inputs?
Yes, enter positive decimal values.
How accurate is the result?
The arithmetic follows the formula; practical accuracy depends on input quality and assumptions.
Can results replace measurements?
No. Use suitable meters, bills, or manufacturer data to verify real conditions.
Are taxes and fixed charges included?
Cost tools calculate only the entered energy-rate relationship unless you add other charges separately.
Does efficiency matter?
It may matter when comparing input and useful output power or energy.
Can this select a breaker?
No. Protection design requires code, conductor, duty, and fault information.
Can I use it for AC?
Use the stated assumptions; AC real-power work may also require phase and power factor.
Why might the real result differ?
Loading, temperature, tolerances, tariffs, harmonics, and measurement accuracy can cause differences.
Can I copy the result?
Yes, use the copy button.
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