kW to kVA

Enter the real power your load consumes and its power factor to get the apparent power a generator, transformer or UPS must supply.

Starting from an apparent-power rating instead? Use the main kVA to kW converter for any power factor.

kW to kVA Calculator

kVA = kW ÷ PF
100 kW
kW
0.8 PF
PF
Quick values

At a glance

kVA = kW ÷ PF
Apparent power
125 kVA
Real power
100 kW
Power factor
0.8 PF

Every diagram and table on this page updates with the calculator above.

Output

Live
Apparent power
125kVA
kVA = 100 kW ÷ 0.8 PF = 125 kVA
Reactive power75 kVAR
Phase angle36.9 °

The kW to kVA Formula

One division, but the number you divide by decides everything downstream — cable size, breaker rating and the generator you end up buying.

kVA = kW ÷ PF

Power factor is a number between 0 and 1, so kVA is never smaller than kW.

  1. Find the real power

    Read the kW figure from the equipment schedule, the motor nameplate or a demand meter. This is the power that actually does work.

  2. Establish the power factor

    Measure it if you can. If not, use 0.80 for a mixed industrial site or 0.85–0.95 for a commercial building with modern equipment.

  3. Divide

    kVA = kW ÷ PF. At 0.80 power factor a 100 kW load needs 125 kVA of supply capacity — 25% more than the kW figure suggests.

Going the other way

To convert kVA back to kW, multiply instead of dividing: kW = kVA × PF. The same power factor applies in both directions.

The conversion

Live
Input100kW
Result125kVA
Live conversion using the values above

What Power Factor Really Tells You

Power factor is the fraction of the current your supply delivers that ends up doing useful work. The rest builds and collapses magnetic fields in motors and transformers, flowing back and forth without producing anything.

Displacement power factor
The classic cosine of the angle between the voltage and current waves. This is what motors and transformers affect.
Distortion power factor
The penalty from harmonic currents drawn by drives, rectifiers and LED drivers. Modern sites often lose more here than to motors.
True power factor
Displacement × distortion. This is what a proper power analyser reports and what your utility bills against.
Load typeTypical PFkVA per 100 kW
Resistive heating, incandescent lighting1.00100 kVA
Modern LED lighting with good drivers0.95105 kVA
Office and data equipment0.90 – 0.95105 – 111 kVA
Mixed commercial / light industrial0.85118 kVA
Motor-heavy workshop0.75 – 0.80125 – 133 kVA
Lightly loaded induction motors0.50 – 0.65154 – 200 kVA

Lightly loaded motors are the worst offenders — a motor at 25% load can drop below 0.5 power factor.

Where your PF sits

Live
Poor
Typical industrial
Good
Corrected
0.8 PF
Your power factor against the bands most sites fall into

Where the Extra kVA Goes

The shortfall between kW and kVA is reactive power, measured in kVAR. It does no work, but it still occupies capacity in every cable, breaker and alternator winding it passes through.

kVA² = kW² + kVAR²

The three quantities form a right triangle; power factor is the cosine of the angle between kW and kVA.

Drag the power factor slider and watch the triangle change shape. As the factor approaches 1 the reactive side shrinks and the hypotenuse falls towards the base — which is exactly what power factor correction does in practice.

Why capacitors help

Capacitors produce leading reactive power that cancels the lagging reactive power drawn by motors. Cancel enough of it and the kVA figure falls without changing the kW at all.

Power triangle

Live
100 kW75 kVAR125 kVAθ = 36.9°
kVA² = kW² + kVAR²

Three Worked Examples

The same arithmetic applied to three very different jobs.

Workshop generator

Given
  • Connected load: 80 kW
  • Measured power factor: 0.80
  • No motor starting allowance yet
Working
  1. kVA = 80 ÷ 0.80
  2. kVA = 100

100 kVA before margin. Add 25% for motor inrush and growth and you are specifying a 125 kVA set.

Office floor after LED retrofit

Given
  • Connected load: 45 kW
  • Power factor improved from 0.85 to 0.95
Working
  1. Before: kVA = 45 ÷ 0.85 = 52.9
  2. After: kVA = 45 ÷ 0.95 = 47.4

The same 45 kW now needs 5.5 kVA less supply capacity — roughly 8 A less per phase at 400 V.

Electric heater bank

Given
  • Connected load: 60 kW
  • Purely resistive, so PF = 1.00
Working
  1. kVA = 60 ÷ 1.00
  2. kVA = 60

For resistive loads kVA equals kW. There is no reactive component to allow for.

Same load, three power factors

Live
At 0.70 PF
Apparent
142.86 kVA
Reactive
102.02 kVAR
At 0.85 PF
Apparent
117.65 kVA
Reactive
61.97 kVAR
At 1.00 PF
Apparent
100 kVA
Reactive
0 kVAR
Your kW figure at three different power factors

kW to kVA Conversion Chart

Common kW ratings converted at the power factor you selected above. Change the slider and every row recalculates.

Standard generator and transformer sizes cluster around these figures, so the nearest row up is usually the unit you will be quoted.

Conversion chart

Live
kWApparent power (kVA)Reactive power (kVAR)
5 kW6.253.75
10 kW12.57.5
15 kW18.7511.25
20 kW2515
25 kW31.2518.75
30 kW37.522.5
40 kW5030
50 kW62.537.5
75 kW93.7556.25
100 kW12575
150 kW187.5112.5
200 kW250150
300 kW375225
400 kW500300
500 kW625375
750 kW937.5562.5
1,000 kW1,250750

Every kW and Power Factor Combination

When you do not know the power factor exactly, read across the row instead of picking a single answer. The spread between the 0.70 and 0.95 columns is the risk you are carrying in your sizing.

  • Reading down a column shows how kVA scales linearly with load.
  • Reading across a row shows how much capacity poor power factor costs you.
  • The highlighted cell follows the calculator, so you can see where your case sits.

kVA lookup grid

Live
kVA for each kW × PF combination
kW0.7 PF0.8 PF0.85 PF0.9 PF0.95 PF1 PF
10 kW14.312.511.811.110.510
25 kW35.731.329.427.826.325
50 kW71.462.558.855.652.650
100 kW142.9125117.6111.1105.3100
150 kW214.3187.5176.5166.7157.9150
250 kW357.1312.5294.1277.8263.2250
400 kW571.4500470.6444.4421.1400

Sizing a Generator from a kW Load

Generators are sold by kVA but rated to deliver their kW figure at a stated power factor — almost always 0.8. Converting your load is the first step; the allowances that follow matter just as much.

  1. Convert the running load

    kVA = kW ÷ PF gives the steady-state capacity the alternator must carry.

  2. Add starting allowance

    A direct-on-line motor draws six to eight times its running current for a few seconds. Size for the largest motor starting while everything else runs.

  3. Allow for growth

    Add 20–25% headroom. A set running permanently near 100% has no margin for a hot day, a new machine or a degraded fuel supply.

  4. Check the step load

    Confirm the frequency and voltage dip when the biggest block of load switches on stays within what your equipment tolerates.

Before you sign the order
  • Is the quoted rating prime, standby or continuous? They are not interchangeable.
  • Does the quoted kVA assume 0.8 power factor? Almost every data sheet does.
  • Have you derated for altitude and ambient temperature at the actual site?
  • Is there a non-linear load share large enough to need an oversized alternator?
  • Can the set take the largest single step load without an unacceptable dip?
Do not undersize on the kW figure alone

Specifying a 100 kVA set for a 100 kW load leaves you 25 kVA short at 0.8 power factor. The set will overload and trip on the first cold start.

Capacity split

Live
How your supply capacity divides
57%
43%
  • Real power (does work)100 kW
  • Reactive power (does not)75 kVAR
The orange share is capacity you pay for but never convert into work

Mistakes That Undersize a Supply

Treating kVA as kW

They are only equal at unity power factor. Assuming equality quietly removes 20–25% of your capacity.

Guessing the power factor

A guess of 0.9 on a site that actually runs at 0.75 undersizes the supply by 20%. Measure where it matters.

Ignoring inrush

Running load is not starting load. Motors draw six to eight times their rated current for the first few seconds.

  • Adding kVA figures from different power factors. Convert everything to kW and kVAR, add those separately, then recombine.
  • Forgetting derating. Altitude, ambient temperature and cable grouping all reduce what the equipment can actually deliver.
  • Correcting power factor too far. Over-correction makes the load capacitive and can raise voltage and excite resonance with harmonics.

What you are paying for

Live
125kVA total
  • Real power100 kW
  • Reactive power75 kVAR
Every kVAR in the ring is capacity that earns nothing

Every Power Converter in One Place

29 calculators built on the same maths as the tool above. Each one has its own inputs, interactive diagrams and worked examples.

View all converters

kW to kVA Questions

Common questions about converting kw to kva.

Divide the real power by the power factor: kVA = kW ÷ PF. For example, 80 kW at 0.80 power factor needs 100 kVA of supply capacity.

100 kW is 125 kVA at 0.80 power factor, 111 kVA at 0.90, and exactly 100 kVA at unity power factor. The answer always depends on the load power factor.

Yes, kVA is always greater than or equal to kW. They are only equal when the power factor is 1.0, which happens with purely resistive loads such as heaters.

Use 0.80 for mixed commercial and industrial loads unless you have measured data. Motor-heavy sites can sit at 0.70–0.75, while modern electronics and corrected installations reach 0.95 or better.

Yes. Add 20–25% for motor inrush and future expansion, then select the next standard generator or transformer size above that figure.

The alternator is limited by current, which follows apparent power, so it is rated in kVA. The engine produces mechanical power, which converts to real power, so it is rated in kW. A 100 kVA set with an 80 kW engine is the standard 0.8 power factor pairing.

Not directly, unless every load has the same power factor. Convert each to kW and kVAR, add those separately, then recombine with kVA = √(kW² + kVAR²).

It does not reduce the energy you consume, but it reduces current, losses and any kVA or power-factor penalty on the bill. On a large industrial tariff that alone often pays for the capacitors.

Most utilities set the threshold at 0.90 or 0.95. Correcting to around 0.95 is the usual target — going much beyond risks over-correction and resonance with harmonics.

Related Converters

Tools that use the same inputs or answer the next question.

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