Watts to VA calculation  Online Electrical Calculators
Watts (W) to Voltamps (VA) Calculator.
Enter Real Power (P) in Watts and Power factor (Pf) and press the Calculator button to get the Apparent Power (VA) in voltamps:
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Note, For higher values like 5×10^{3}, 10×10^{6}, 1.6 x10^{12}, enter the value like this for scientific notation as 5e3, 10e6, 1.6e12, etc.
Conversion Using the Power Formula :
AC Single Phase Watts to VA Calculation:
The Apparent Power (S) in Voltamps (VA) is equal to the Real Power (P) in Watts (W), Divided by the Power factor (pf):
For example, If an Induction motor takes 5kW active power at 0.90 (lag) power factor from the AC source. Calculate the VA rating of the motor.
S_{(VA)} = P_{(W)} ÷ pf
S_{(VA)} = 5000 ÷ 0.90
VA= 5555
Where:

 S = Apparent Power in VA
 P = Real Power in Watts
 Cosθ = Power factor in AC circuits
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How to use This Calculator?
To use the above “Watts (W) to Voltamps (VA) Conversion Calculator” follow the below steps:
1. Enter Supply Voltage: Input the supply voltage or motor voltage value in the specified input box. You can enter the value in Volts or Kilovolts by choosing the appropriate option from the dropdown.
2. Enter Power Factor: Input the power factor of the motor in the provided input box. The power factor is a unitless value typically between 0 and 1.
3. Reset: Click the “Reset” If you want to reset the calculator to perform another conversion, you can click the “Reset” button, and all input fields will be cleared.
4. Calculate: Click the “Calculate” button to obtain the results. The calculated results will be displayed in the “Results:” section.
5. Swap: If you want to “Swap” the calculated to Exchange conversion, you can click the “Swap” button, and Calculate will be Exchange.
6. Result: The calculated “result” will be displayed in the respective “Result In voltamps (VA)” output field.
Watts (W) to Voltamps (VA) Conversion table:
Power (watts)  Power Factor (Pf)  VA Rating 

500W  0.90  555 
750W  0.90  833 
1000W  0.90  1111 
1250W  0.90  1388 
1500W  0.90  1666 
1750W  0.90  1944 
2000W  0.90  2222 
2250W  0.90  2500 
2500W  0.90  2777 
2750W  0.90  3055 
3000W  0.90  3333 
3250W  0.90  3611 
3500W  0.90  3888 
3750W  0.90  4166 
4000W  0.90  4444 
4250W  0.90  4722 
4500W  0.90  5000 
4750W  0.90  4944 
5000W  0.90  5555 
5250W  0.90  5833 
Power Factor Value 0.9 
Device  Typical PF 

Resistive Load  1 
Fluorescent Lamp  0.95 
Incandescent Lamp  1 
Induction Motor full load  0.85 
Induction Motor no Load  0.35 
Resistive Oven  1 
Synchronous Motor  0.9 
Power Factor Value conversion table 
Frequently asked questions
A watt changes depending on whether the electrical circuit is AC or DC. In a DC circuit, 111 VA is the equivalent of 100 W. This equivalence means that the power factor of that power supply is 0.90.
Use the following formula to calculate VA from watts: Apparent Power(VA) = Real Power in Watts / Power factor in PF.
Here rating of the inverter is 850 VA, so it can handle 850 VA maximum. Considering the power factor of 0.80, the total wattage will be 850 X 0.9 = 765 Watts.
That 1500VA (or 1500Watt) means that the UPS can deliver 1500W maximum. It has no relation to the battery capacity nor how much current is used to charge the battery.
A voltamps x power factor = watts. When you want to know how much the electricity is costing you, you use watts. When you are specifying equipment loads, fuses, and wiring sizes you use the VA, or the voltage times the amperage.