Free tool
kVA to kW Calculator
Real power is apparent power times the power factor. A nameplate that already lists both is not asking you to invent a third number.
kW = kVA × power factor
kW = kVA × PF. A 100 kVA rating at a power factor of 0.8 is 80 kW. At a power factor of 1.0 the two figures are the same. The tool also shows the reactive component and checks a nameplate that already prints both kVA and kW, so a mismatch is flagged rather than averaged.
This is unit conversion, not generator sizing. Current still follows the kVA — convert that separately with the kVA to amps calculator.
The rating
Enter 500 VA as 0.5.
From the nameplate when it states one. Otherwise a known load PF.
0.80 — conservative motor / lightly loaded
The answer
Real power
80.00 kW
kW = kVA × PF → 100.00 × 0.80 = 80.00 kW
At unity power factor the two figures are equal. At PF 0.80, only 80% of the apparent power is real power the load can use as work or heat — the rest is reactive.
Also true at this PF
Reactive power ≈ 60.00 kvar (from √(kVA² − kW²)). Apparent power stays 100.00 kVA. Current is set by the kVA, not by the kW — which is why a kVA to amps conversion does not take a power factor.
What this does not tell you
Current. Use the kVA and the voltage for that — not the kW. A breaker or conductor size. Those depend on continuous-load rules, ambient temperature and terminal ratings. Whether a machine is large enough for a building. That is load calculation, not unit conversion.
Informational use only, please verify before you rely on it
This reproduces the standard relationship between apparent power in kVA and real power in kW. It is a preparation aid, not a determination and not a design. It does not size generators, transformers, conductors or overcurrent protection, and it does not calculate the load a building will place on a machine. Confirm against the equipment nameplate and with the authority having jurisdiction.
This tool is provided for general informational and educational purposes only. Its output is an illustrative estimate generated from the values you enter and from general assumptions that will not match every deal, market, lender, or homeowner. It is not tax, legal, accounting, financial, or professional advice, and it is not a quote, an offer, a credit decision, or a guarantee of pricing, approval, timing, savings, or eligibility.
You are solely responsible for independently confirming all information presented here including any figures, rates, fees, margins, timelines, tax treatment, and federal, state, local, or utility incentives, with the applicable lender, authority having jurisdiction, and your own qualified tax, legal, and financial advisors before acting on it, relying on it, or presenting it to a homeowner or any third party. Incentive programs, lender terms, and permitting requirements change frequently and vary by jurisdiction.
Seamless Home is not a tax advisor, law firm, lender, or licensed installing contractor, and makes no representation or warranty as to the accuracy, completeness, or currency of the information produced by this tool. To the fullest extent permitted by law, Seamless Home accepts no liability for any decision made or action taken in reliance on it.
Where the power factor has to be real
On a transformer or UPS the kVA rating is the thermal limit of the machine. The real power it can deliver to a load depends on that load's power factor — which is why the same kVA nameplate supports different kW figures on a heater and on a bank of motors. What power factor is covers the ratio; the kW to amps calculator goes the other way when the rating you have is already in kW.
Generators that print both kVA and kW are stating two limits, not inviting a conversion. Read the plate. If you need current from the kVA figure, use kVA to amps; if you started from kW instead, the kW to kVA calculator is the inverse of this page.
Frequently Asked Questions
How do you convert kVA to kW?+
Multiply kVA by the power factor: kW = kVA × PF. A 100 kVA transformer at a power factor of 0.8 delivers 80 kW of real power. At unity power factor the two figures are equal. Power factor must be known — it cannot be invented from the kVA alone.
What is the difference between kVA and kW?+
kVA is apparent power, volts times amps, which is what wiring and transformers carry. kW is real power, the part that does work or becomes heat. The ratio between them is the power factor. A motor or electronic load draws more apparent power than real power; a resistive heater draws the same amount of both.
Why does a generator list both kVA and kW?+
Because its thermal and magnetic limits are stated in kVA, while the real power it can deliver continuously is stated in kW at a rated power factor — often 0.8. A 100 kVA / 80 kW nameplate is telling you both limits. Converting one without reading the other invents a figure the plate already printed.
Does this size a generator for a house?+
No. It only converts units. Sizing a generator needs the running and starting loads of the equipment it will serve, which is a different calculation. A residential-looking kVA figure converts the same way as any other — it is not a recommendation that the figure is the right size.
How do I get amps from kVA?+
Divide kVA × 1,000 by the voltage (and by √3 on three-phase line-to-line). Power factor does not enter that conversion, because kVA is already apparent power. The kVA to amps calculator does that step and flags the common voltage mistakes.
What power factor should I use?+
The one on the nameplate when it states one. For a known load, use that load's power factor — about 1.0 for heaters, often 0.8 to 0.9 for motors under load, and higher for modern power-factor-corrected electronics. Guessing 0.8 for everything is a rule of thumb, not a measurement.
Is this a determination?+
No. It reproduces the standard relationship kW = kVA × PF as a preparation aid. It does not size conductors, overcurrent protection, transformers or generators, and it does not replace a load calculation. Confirm against the equipment nameplate and with the authority having jurisdiction.
Related resources
kW to kVA Calculator
The inverse conversion — with motor shaft kW handled as output, not input.
Learn more →kVA to Amps Calculator
Full-load current from a kVA rating, with the voltage mistakes flagged.
Learn more →What Is Power Factor?
Why kW and kVA part company on motors and electronics.
Learn more →kW to Amps Calculator
Current from a kW rating, including a motor's shaft output.
Learn more →Ratings that have to survive the job
Seamless Home runs the design, permit and interconnection layer for the partners it works with — which is where a transformer or generator rating gets checked against the load rather than against a rule of thumb. Coverage is confirmed per service area rather than promised as blanket availability.
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