kVA Calculator

Created by Kenneth Alambra
Last updated: Aug 24, 2022

This Volts and Amps to kVA calculator will help you determine the apparent power you can draw from an electrical system. But what is kVA? Keep on reading to learn:

  • What kVA is;
  • How to calculate kVA; and
  • How to use this Volts and Amps to kVA calculator.

What does kVA mean?

kVA is an abbreviation for kilovolt-amperes, which is a unit of apparent power. Apparent power is the power that we can potentially draw from an electrical power system. We can determine the amount of apparent power by multiplying together the rated voltage and amperage of the electrical system.

As a result, we get an apparent power with the unit of volt-amperes. Dividing that value by 1000 gives us kilovolt-amperes as its unit of measure.

However, you might be wondering about its difference from watts. Watt is also a unit of power, but more specifically, real power. We can obtain the amount of real power we can get from an electrical system by multiplying its apparent power by what we call the power factor.

Let's discuss more of the relationship between these parameters in the next section of this text.

💡 If you want to learn more about the power factor, we have a power factor calculator waiting for you. 🙂

How to calculate kVA

As mentioned above, we determine kVA by taking the product of the voltage and amperage of our electrical system. However, we must consider several factors since our electrical system can have a few different load distribution configurations.

With that said, here are the three different apparent power formulas for each typical load distribution:

For single-phase power systems:

S=V×IS = V\times I

For 3-phase power system with line-to-line voltage:

S=3×VL-L×IS = \sqrt{3}\times V_{\text{L-L}}\times I

For 3-phase power system with line-to-neutral voltage:

S=3×VL-N×IS = 3\times V_{\text{L-N}}\times I

Where:

  • SS is the apparent power in kVA;
  • VV is the voltage in kilovolts;
  • VL-LV_{\text{L-L}} is the line-to-line voltage in kilovolts;
  • VL-NV_{\text{L-N}} is the line-to-neutral voltage in kilovolts; and
  • II is the current amperage in amperes.

After calculating the apparent power, if we know our device's power factor, we can also determine its real power using this formula:

P=S×PFP = S\times \text{PF}

Where:

  • PP is the real power in kW;
  • SS is the apparent power in kVA; and
  • PF\text{PF} is the power factor that can have values from 0 to 1.

How to use this volts and amps to kVA calculator

Let's say we want to find the apparent power and real power that flows through a pump connected to a single-phase 220-volt power system at 15 amperes of current. Say our pump is rated with a power factor of 0.8. We can manually calculate it, but we can also use our kVA calculator for it. Here are the steps you can follow:

  1. Select Single phase for the load distribution.
  2. Enter 220 V for the voltage.
  3. Input 15 A for the electric current's amperage.
  4. Expect a value of 3.3 kVA for the apparent power in the output value section of our tool.

We can also substitute the values to our formula to have:

S=V×A=220 V×15 A=3300 VA=3.3 kVA\begin{align*} S &= V\times A\\ &= 220\ \text{V}\times 15\ \text{A}\\ &= 3300\ \text{VA}\\ &= 3.3\ \text{kVA} \end{align*}

To find the real power using our kVA calculator, you must first access its advanced mode feature by clicking on the Advanced mode button below it. Then enter 0.8 for the power factor. Our kVA calculator will then display 2.64 kW for our pump's real power.

Here is to show how we arrive at that number:

P=S×PF=3.3 kVA×0.8=2.64 kW\begin{align*} P &= S\times \text{PF}\\ &= 3.3\ \text{kVA}\times 0.8\\ &= 2.64\ \text{kW} \end{align*}
Kenneth Alambra
Input values
Load distribution
Single phase
Voltage (V)
V
Current (I)
A
Output value
Apparent power (S)
kVA
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