Convert KVA to KW, KW to KVA, KW to KWh, KWh to KW, KVA to VA, VA to KVA, and calculate KVAR — all 7 power unit conversion modes for generators, transformers, UPS, and industrial electrical systems.
✓Verified: IEEE Std 100 Power Triangle & IEC 60038
Generator, transformer, or UPS ratingEnter a valid KVA value.
Typical: motors 0.8–0.95 | resistive loads 1.0Enter PF between 0.01 and 1.0.
Motor output or load real powerEnter a valid KW value.
Enter load power factorEnter PF between 0.01 and 1.0.
Average power in kilowattsEnter a valid KW value.
Duration of use in hoursEnter a valid number of hours.
Energy consumed in kilowatt-hoursEnter a valid KWh value.
Duration of use in hoursEnter a valid number of hours.
Select conversion directionSelect direction.
Enter the value to convertEnter a valid value.
Select what to calculateSelect option.
First known valueEnter a valid value.
Second known valueEnter a valid value.
Enter your total load in KW, the system power factor, and a safety margin to find the required generator KVA rating.
Sum of all load KW valuesEnter a valid KW total.
Overall PF of all loads combinedEnter PF 0.01–1.0.
Always oversize generatorsSelect margin.
Result
--
⚠️ Disclaimer: Results use standard electrical engineering formulas (Power Triangle: KVA² = KW² + KVAR²). For generator and transformer sizing, always consult a qualified electrical engineer and verify with equipment datasheets.
Was this calculator helpful?
✓ Thanks for your feedback!
📚 Sources & Methodology
All power conversion formulas are verified against:
IEEE Std 100-2000 — IEEE Standard Dictionary: KVA, KW, KVAR, power factor, and power triangle definitions standards.ieee.org
IEC 60038:2009 — IEC standard voltages and power system design iec.ch
NFPA 70 NEC 2023, Article 445 — Generators: sizing, ratings, and installation requirements nfpa.org
KVA, KW, KWh & KVAR — Complete Power Conversion Guide
The Power Triangle: KVA, KW, and KVAR
The three types of electrical power form a right triangle. Real power (KW) is the horizontal leg — it does useful work (heat, mechanical output). Reactive power (KVAR) is the vertical leg — it is stored and returned by inductors and capacitors but does no net work. Apparent power (KVA) is the hypotenuse — the total power the source must supply. The Pythagorean relationship holds: KVA² = KW² + KVAR².
Power Triangle Formulas
KW = KVA x PF (real power)KVA = KW / PF (apparent power)KVAR = SQRT(KVA^2 - KW^2) (reactive power)PF = KW / KVA = cos(phi) (power factor)Phase angle phi = arccos(PF)KWh = KW x Hours (energy consumed)KW = KWh / Hours (average power demand)
KVA vs KW: Why the Distinction Matters
Generators, transformers, and UPS systems are rated in KVA because they must supply all apparent power regardless of what fraction is real power. A 10 KVA generator with a PF=0.8 load delivers only 8 KW of useful power — but must still supply 10 KVA of apparent power. If the same generator powers a resistive load (PF=1.0), it delivers the full 10 KW.
This is why you cannot simply match KW load to KVA generator rating. A 10 KW motor load at PF=0.85 requires 10/0.85 = 11.76 KVA from the generator. Adding the 25% sizing margin: 14.7 KVA — select a 15 KVA generator.
KW to KWh: Power vs Energy
KW (kilowatts) is instantaneous power — the rate of energy use. KWh (kilowatt-hours) is energy — power accumulated over time. A 5 KW motor running 8 hours uses 40 KWh. Your utility bills you for KWh. To find average power demand from your utility bill: divide monthly KWh by operating hours. 900 KWh consumed over a month (720 hours) = average demand of 900/720 = 1.25 KW.
Quick KVA to KW Reference (PF = 0.8)
KVA
KW (PF=0.80)
KW (PF=0.90)
1 KVA
0.80 KW
0.90 KW
5 KVA
4.00 KW
4.50 KW
10 KVA
8.00 KW
9.00 KW
25 KVA
20.00 KW
22.50 KW
50 KVA
40.00 KW
45.00 KW
100 KVA
80.00 KW
90.00 KW
250 KVA
200.0 KW
225.0 KW
500 KVA
400.0 KW
450.0 KW
KW
KVA (PF=0.80)
KVA (PF=0.90)
1 KW
1.25 KVA
1.11 KVA
5 KW
6.25 KVA
5.56 KVA
10 KW
12.50 KVA
11.11 KVA
25 KW
31.25 KVA
27.78 KVA
50 KW
62.50 KVA
55.56 KVA
100 KW
125.0 KVA
111.1 KVA
250 KW
312.5 KVA
277.8 KVA
500 KW
625.0 KVA
555.6 KVA
Power Factor Correction
Low power factor increases current demand without increasing useful work, wasting energy in I²R losses. Capacitor banks supply reactive power locally, reducing KVAR demand from the utility. A 100 KW load at PF=0.70 draws 142.9 KVA. Correcting to PF=0.95 reduces to 105.3 KVA — a 26% reduction in apparent power. Industrial facilities with PF below 0.9 often face reactive power charges from utilities.
💡
Generator sizing rule: Never load a generator above 70–80% of its rated KVA under continuous operation. Always apply a 25% minimum margin over calculated KVA. For motor-dominated loads (compressors, pumps), use 30–50% margin to handle starting surge currents, which can be 6–8x running current.
❓ Frequently Asked Questions
KW = KVA x Power Factor. Example: 10 KVA at PF=0.8 = 8 KW. At PF=0.95 = 9.5 KW. At PF=1.0 (resistive) = 10 KW. Power factor ranges from 0 (purely reactive) to 1.0 (purely resistive). Most industrial loads have PF of 0.75 to 0.90. Use the KVA to KW tab above for any value.
KVA = KW / Power Factor. A 15 KW motor at PF=0.85: KVA = 15/0.85 = 17.65 KVA. This is what the supply source (generator, transformer) must be rated for. Always divide KW by PF — never multiply — when sizing equipment to supply a KW load.
KWh = KW x Hours. A 3 KW motor running 6 hours: 3 x 6 = 18 KWh. KW is instantaneous power; KWh is total energy over time. Your electricity bill charges for KWh. Annual KWh = KW x daily_hours x 365.
KVA is apparent power (what the source must supply). KW is real power (useful work done). KWh is energy (KW x time). Relationship: KW = KVA x PF. KWh = KW x hours. Generators are rated KVA. Motors are rated KW or HP. Your electricity bill is in KWh. Power factor is the ratio KW/KVA.
KVAR (kilovolt-ampere reactive) is reactive power - stored and returned by inductors/capacitors each cycle. KVAR = SQRT(KVA^2 - KW^2). For a 10 KVA, 8 KW load: KVAR = SQRT(100-64) = SQRT(36) = 6 KVAR. To correct PF to 1.0, add 6 KVAR of capacitors at the load. The power triangle: KVA^2 = KW^2 + KVAR^2.
Total KW / PF = base KVA. Add 25% margin: base KVA x 1.25 = required KVA. Example: 20 KW total loads, PF=0.8: 20/0.8 = 25 KVA base x 1.25 = 31.25 KVA. Select 35 KVA generator (next standard size up). For motor-heavy loads use 30-50% margin for starting surges. Never load a generator above 80% continuously.
VA = KVA x 1000. KVA to VA simply multiplies by 1,000 (kilo = 1,000). 5 KVA = 5,000 VA. 0.75 KVA UPS = 750 VA. To convert VA back to KVA: divide by 1,000. These units are identical in meaning, just different scales. VA is used for small loads; KVA for larger equipment.
UPS KVA = Load watts / PF / 1000. Computer server at 900W, PF=0.9: 900/0.9/1000 = 1.0 KVA. Add 20-25%: 1.25 KVA minimum. Select 1.5 KVA UPS. Modern online UPS units show both KVA and KW ratings (KW is always smaller). Match the load watts to the KW rating. Check runtime requirements separately based on battery AH capacity.
3-phase KVA = V x I x 1.732 / 1000. Or from KW: KVA = KW / PF (same formula). To find amps from KVA: I = KVA x 1000 / (V x 1.732). Example: 50 KVA 3-phase at 480V: I = 50,000/(480 x 1.732) = 60.1 amps per phase. The 1.732 factor (sqrt of 3) comes from the 120-degree phase separation in 3-phase systems.
KW = KWh / Hours. Divide energy by time to get average power. A device that used 24 KWh over 6 hours drew an average of 24/6 = 4 KW. From a utility bill: 900 KWh/month over 300 operating hours = 3 KW average demand. This helps size backup generators and identify high-consumption loads.
Reactive power (KVAR) is power oscillating between the source and inductive/capacitive loads each AC cycle. It does no real work but increases current, causing I^2R losses in cables and transformers. Low PF = high KVAR = higher losses. Power factor correction capacitors supply KVAR locally, reducing what the utility supplies. Utilities charge commercial customers for reactive power consumption (KVAR demand charges) when PF falls below 0.9.
HP = KVA x PF x Efficiency / 0.746. KVA to HP for a motor: KVA=10, PF=0.85, efficiency=90%: HP = 10 x 0.85 x 0.90 / 0.746 = 10.24 HP. Reverse: KVA = HP x 0.746 / (PF x Efficiency). 10 HP motor: KVA = 10 x 0.746 / (0.85 x 0.90) = 9.76 KVA. The constant 0.746 converts KW to HP (1 HP = 746 W).