kW to kVAR Calculator
Instant power factor correction calculator: enter load kW, existing PF, and target PF to screen capacitor bank ΔkVAR. Also converts kW ↔ kVAR at one PF. Example: 100 kW from 0.80 → 0.95 PF ≈ 42.1 kVAR. Formula: PF = kW ÷ kVA.
Calculator
Quick (default): PF correction existing → target. Advanced: single-PF kW→kVAR or reverse.
About this calculator
This power factor correction calculator screens capacitor bank kVAR from load kW and PF targets (ΔkVAR = Q₁ − Q₂). Single-PF mode still converts kW to kVAR for the power triangle. Part of the Power Calculator hub (featured topic).
Calculation Results
Engineering disclaimer
Estimate only—harmonics, leading PF, and unbalance need site measurements. Final capacitor bank design requires engineering review.
Power factor correction ladder (ΔkVAR)
ΔkVAR = Q₁ − Q₂ for capacitor screening. Click a row to load existing → target PF in the calculator (same formula Schneider/SE-style tools use for bank sizing).
| Load kW | Existing → Target | ΔkVAR | Open |
|---|---|---|---|
| 50 | 0.80 → 0.95 | 21.07 | |
| 100 | 0.80 → 0.95 | 42.13 | |
| 200 | 0.80 → 0.95 | 84.26 | |
| 100 | 0.80 → 0.90 | 26.58 | |
| 100 | 0.85 → 0.95 | 29.02 | |
| 100 | 0.85 → 0.98 | 41.61 | |
| 100 | 0.90 → 0.98 | 28.17 | |
| 250 | 0.80 → 0.95 | 105.33 |
Single-PF kW→kVAR chart (PF 0.85): 10 kW ≈ 6.19 kVAR · 50 kW ≈ 30.95 kVAR · 100 kW ≈ 61.89 kVAR — switch mode to kW → kVAR.
Formula & Explanation
How to calculate power factor correction:
- Enter load kW (real power from meters or nameplate roll-up).
- Set existing PF (measured lagging) and target PF (often 0.95).
- Read ΔkVAR = Q₁ − Q₂ where
Q = kW × tan(arccos PF). - Screen capacitor bank steps, then review harmonics / leading PF on site.
Power factor correction formula: ΔkVAR = Q₁ − Q₂. Equivalent: kVA = kW ÷ PF and kVAR = √(kVA² − kW²) at each PF.
Example: 100 kW from PF 0.80 → 0.95 → Q₁ ≈ 75.00 kVAR, Q₂ ≈ 32.87 kVAR, capacitors ≈ 42.13 kVAR.
See also kW to kVA, 3-phase power, capacitor bank sizing, and the power factor formula.
Learn About Power Factor
Understand power factor formulas, typical industrial values, correction methods, and utility penalty rules in our central topic guide.
Typical motor reactive power (PF 0.85)
| Load | kW | kVAR |
|---|---|---|
| Small motor | 7.5 | 4.64 |
| Medium motor | 30 | 18.57 |
| Plant block | 200 | 123.78 |
Frequently Asked Questions
Is this a power factor correction calculator?
Yes. Default mode sizes capacitor ΔkVAR from load kW, existing PF, and target PF. Single-PF mode still converts kW to kVAR. For PF = kW ÷ kVA, use the Power Factor Formula guide.
How to calculate power factor correction?
Use ΔkVAR = Q₁ − Q₂ with Q = kW × tan(arccos PF) between existing and target PF. Example: 100 kW from 0.80 → 0.95 ≈ 42.1 kVAR. Default mode on this page is the power factor correction calculator workflow.
How much power factor correction do I need?
Enter kW + existing/target PF. Required capacitors ≈ ΔkVAR = Q₁ − Q₂. Example: 100 kW from 0.80 → 0.95 ≈ 42.1 kVAR. Harmonics and leading PF need field review.
How to do a power factor correction?
Measure plant PF and kW → screen capacitor ΔkVAR here → choose fixed/switched banks → check harmonics and utility rules. Guides: capacitor bank sizing and harmonics in PFC.
How much money can power factor correction save?
It depends on your tariff (kVAR charges, demand, penalties)—this tool does not guarantee dollar savings. Screen kVAR here, then check your rate schedule and the PF penalty guide.
How do I calculate capacitor bank size for power factor correction?
Use mode PF correction (target PF → ΔkVAR): enter load kW, existing PF, and target PF. Or single-PF kVAR = √(kVA² − kW²). See capacitor bank sizing guide.
What is PF penalty in an electricity bill?
Utilities charge when power factor falls below a threshold (often ~0.90–0.95). Low PF raises apparent power (kVA) and reactive demand. Estimate kVAR here, then read PF penalty rules & cost impact.
How do I convert kW to kVAR?
Find kVA = kW ÷ PF, then kVAR = √(kVA² − kW²). Example: 10 kW @ 0.85 PF → 6.19 kVAR. Use the calculator.
Is kVAR equal to kW?
No. kW is real power; kVAR is reactive. They match only at PF 1.0 when kVAR = 0.
What does a PF of 80% mean?
PF 0.80 means 80% of apparent power is real; the rest is reactive. 10 kW @ 0.80 PF → kVA 12.5, kVAR ≈ 7.5. Compare with 10 kW @ 0.80 PF preset.
What is kVAR vs kW?
kW does useful work; kVAR supports magnetic fields in motors and transformers. Utilities and capacitors care about kVAR for PF correction.
How much kVAR for 50 kW at 0.85 PF?
About 30.95 kVAR lagging (kVA ≈ 58.82). Open 50 kW preset.
What is the reactive power formula?
kVAR = √(kVA² − kW²) with kVA = kW ÷ PF, or kVAR = kW × tan(arccos PF). Three-phase reactive power uses the same triangle after you have total kW and PF—this calculator returns plant kVAR for correction screening.
What are the units of reactive and apparent power?
Reactive power uses kVAR (or VAR); apparent power uses kVA (or VA); real power uses kW. They are not interchangeable except at PF 1.0 when kVAR = 0.