Conversion using the Watts to VA Formula
Watts to VA Calculation formula
The Apparent Power S in volt-amps va is calculated as the Real Power P in Watts w, divided by the Power factor in pf. Plug these values into the formula:
For Example, If an Induction motor takes 10kW active power at 0.80 (lag) power factor from the AC source. Calculate the VA rating of the motor.
Suggested Reading
- Watts (W) to Volt-amps (VA) Conversion Calculator
- Joules (J) to Volts (V) Conversion Calculator
- Kilowatts (KW) to Watt-hours (WH) Conversion Calculator
- Kilowatt-hours (KWh) to Milliamp-hour (mAh) Conversion Calculator
- Kilowatts (KW) to kilowatt-hour (Kwh) Conversion Calculator
- Milliamp-hour (mAh) to Watt-hour Conversion Calculator
- Kilowatts (KW) to amps (A) Conversion Calculator
- Kilowatts (Kw) to Volt-amps (VA) Conversion Calculator
- Watt-hour (Wh) to Milliamp-hour (mAh) Conversion Calculator
- Joules (J) to Kilowatts (KW) Conversion Calculator
- Kilowatt-hours (KWh) to Watts (W) Conversion Calculator
- Kilowatts (KW) to kilovolt-amps (KVA) Conversion Calculator
How to use Watts to VA Calculator?
To use the above "Watts to VA Conversion Calculator" follow the below steps:
1. Enter Real Power: Input the Real Power in watts or Load watts value in the specific input box. You can enter the value in millivolts mw, Watts W, kilowatts KW, & Megawatts MW by choosing the appropriate option from the dropdown.
2. Enter Power Factor: Input the power factor of the Load 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 output VA output field.
Watts to VA or KVA Comparison and Sizing Table
| Input | Output | ||
|---|---|---|---|
| Watts [W] |
Power factor [PF] |
Apparent Power [VA] |
Apparent Power [KVA] |
| 10W | 0.8PF | 12.5000VA | 0.0125KVA |
| 20W | 0.8PF | 25VA | 0.0250KVA |
| 30W | 0.8PF | 37.5000VA | 0.0375KVA |
| 40W | 0.8PF | 50VA | 0.0500KVA |
| 50W | 0.8PF | 62.5000VA | 0.0625KVA |
| 60W | 0.8PF | 75VA | 0.0750KVA |
| 70W | 0.8PF | 87.5000VA | 0.0875KVA |
| 80W | 0.8PF | 100VA | 0.1000KVA |
| 90W | 0.8PF | 112.5000VA | 0.1125KVA |
| 100W | 0.8PF | 125VA | 0.1250KVA |
| 1000W | 0.8PF | 1250VA | 1.2500KVA |
Typical power factor values
Do not use typical power factor values for accurate calculations.
| Equipment and appliances | cos θ | tan θ | |||
|---|---|---|---|---|---|
| Motor | Common induction motor | loaded at | 0 % | 0.17 | 5.80 |
| 25% | 0.55 | 1.52 | |||
| 50 % | 0.73 | 0.94 | |||
| 75 % | 0.80 | 0.75 | |||
| 100 % | 0.85 | 0.62 | |||
| Lamps | Incandescent lamps | 1.0 | 0 | ||
| Fluorescent lamps (uncompensated) | 0.5 | 1.73 | |||
| Fluorescent lamps (compensated) | 0.93 | 0.39 | |||
| Discharge lamps | 0.4 to 0.6 | 2.29 to 1.33 | |||
| Ovens | Ovens using resistance elements | 1.0 | 0 | ||
| Induction heating ovens (compensated) | 0.85 | 0.62 | |||
| Dielectric type heating ovens | 0.85 | 0.62 | |||
| Welding | Resistance-type soldering machines | 0.8 to 0.9 | 0.75 to 0.48 | ||
| Fixed 1-phase arc-welding set | 0.5 | 1.73 | |||
| Arc-welding motor-generating set | 0.7 to 0.9 | 1.02 to 0.48 | |||
| Arc-welding transformer-rectifier set | 0.7 to 0.8 | 1.02 to 0.75 | |||
| Arc furnace | 0.8 | 0.75 | |||
| Power Factor Value Conversion Table | |||||
Frequently Asked Questions - FAQs for Watts to VA Calculator
A volt-amps × 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.
Use the following formula to calculate VA from watts: Apparent Power(VA) = Real Power in Watts ÷ Power factor in PF.
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.
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 × 0.9 = 765 Watts.
A watt changes depending on whether the electrical circuit is AC or DC. In a DC circuit, 1200VA is the equivalent of 200W. This equivalence means that the power factor of that power supply is 0.90.
About the Author
