Bill calculator
Power factor penalty calculator: what low PF costs you each month.
Enter one month from your electricity bill. See the extra units or surcharge, the extra demand charge, and the capacitor kVAr needed to reach your target power factor.
Low power factor costs about₹83,446a month · ₹10,01,352 a year
- Billed units now
- 1,11,111 kVAh
- Billed units at target PF
- 1,02,041 kVAh
- Extra units from low PF
- 9,070 kVAh
- Energy charge
- ₹8,00,000
- PF surcharge now
- ₹0 (0%)
- PF surcharge at target PF
- ₹0 (0%)
- Energy cost of low PF
- ₹72,562
- Peak demand now → at target
- 444 → 408 kVA
- Demand charge saved
- ₹10,884
- Capacitor to reach target
- 113 kVAr
Illustrative defaults — replace them with your own bill and tariff. Assumes lagging power factor; electricity duty, fuel surcharge and rebates are not included. The demand saving applies where demand is billed in kVA and sits above any minimum billing demand; set the demand charge to 0 if yours is billed in kW.
How the calculator works
- Billed units on a kVAh tariff. The average power factor on your bill is kWh ÷ kVAh, so billed kVAh = kWh ÷ PF. The extra units are the difference between your power factor now and your target, for the same kWh.
- PF surcharge on a kWh tariff. Worked out as a percentage of the energy charge for each 0.01, or part of it, that power factor is below the threshold. Some tariffs use paise per unit instead, or pay an incentive above a higher power factor — enter the figures from your own tariff order.
- Demand. At your peak load, kVA = kW ÷ PF. The saving is the fall in kVA at the target power factor, times your demand charge.
- Capacitor size. kVAr = kW × (tan φ now − tan φ at target), where cos φ is the power factor, worked out at your peak load.
The kVAr figure is for your peak load. At light load the same capacitance can push power factor leading, which many kVAh tariffs also bill. Correction in steps that an APFC panel switches with the load avoids that.
What a monthly average hides
A bill shows one average. Power factor can sit near unity through the day shift and fall away at night, on weekends, or on one feeder whose capacitor step has failed. The average tells you what it cost — not which panel, or which hours, to fix. See what drags power factor down.
How KONDUKTOR® EMS helps
KONDUKTOR® EMS reads the multifunction meters already on your panels and shows live power factor for every meter against a 0.95 target, with lead or lag marked.
- Low-PF alerts tell your team the moment a panel slips, instead of at the end of the month.
- The power factor optimiser estimates the capacitor kVAr needed to reach your target and the rupee saving it would bring.
- History by shift and by panel shows when PF drops, and where — so the fix goes to the right feeder.
Common questions
How do I find my average power factor from the bill?+
Divide the month’s kWh by its kVAh. Many bills also print the average power factor directly, next to the meter readings.
Is the capacitor kVAr from this calculator enough to order a panel?+
It is a starting point. Before ordering, check the load through the day, the health of the capacitors already installed, and harmonics from drives. Correction in steps that follow the load avoids overcorrecting when the plant runs light.
Why does a small power factor change save so much on a kVAh tariff?+
Because every unit is billed as kWh ÷ PF. Moving from 0.90 to 0.98 cuts billed kVAh by about 8% for the same production, on every hour of the month.
Get these numbers from your own meters, live.
Book a live demo and see per-meter power factor, low-PF alerts and capacitor sizing on meters like yours.