Power Factor Calculators

Three-Phase System

3-Phase kVAr Calculator

For industrial loads connected to a 3-phase supply (415V typical). Enter load, existing and target power factor to find the required capacitor bank size.

Single-Phase System

Single-Phase kVAr Calculator

For single-phase loads. Enter current load in kW, existing and target power factor to calculate the required capacitor bank size.

Calculation Method

How We Calculate

3-Phase kVAr Formulas

kVAr

= kW × ( tan(cos⁻¹ PF₁) − tan(cos⁻¹ PF₂) )

kW = Active load power | PF₁ = Existing power factor | PF₂ = Target power factor

kVA

= kW ÷ PF₁

kVA = Apparent power drawn from supply

I (A)

= ( kVA × 1000 ) ÷ ( √3 × V )

I = Full load current | V = Line-to-line voltage (e.g. 415 V) | √3 ≈ 1.732

tan θ

= √( 1 − PF² ) ÷ PF

Derived from the power triangle: kVAr = kVA × sin θ, kW = kVA × cos θ

Single-Phase kVAr Formulas

kVA

= ( V × I ) ÷ 1000

V = Supply voltage (e.g. 230 V) | I = Load current in Amperes

= kVA × PF₁

kW = Active power (stays constant before & after correction)

Q₁ (kVAr)

= kW × tan(cos⁻¹ PF₁)

Q₁ = Existing reactive power before correction

kVAr

= kW × ( tan(cos⁻¹ PF₁) − tan(cos⁻¹ PF₂) )

kVAr = Capacitor bank rating required | PF₂ = Desired target power factor

Variable Reference

kW — Active (real) power in kilowatts

kVA — Apparent power in kilovolt-amperes

kVAr — Reactive power / capacitor bank size in kilovolt-amperes reactive

PF₁ — Existing (current) power factor — between 0.01 and 1.00

PF₂ — Target (desired) power factor — typically 0.95–0.99

V — Supply voltage in Volts

I — Load current in Amperes

cos⁻¹ — Arc-cosine (inverse cosine) function

√3 — Square root of 3 ≈ 1.7321 (3-phase factor)

How It Works

Understanding Power Factor

What is Power Factor?

Power factor (PF) is the ratio of active power (kW) to apparent power (kVA). A PF of 1.0 is ideal — all supplied power is used productively. Low PF means wasted energy and higher electricity bills.

Why Use Capacitors?

Capacitor banks supply reactive power locally, reducing the reactive current drawn from the grid. This corrects poor power factor, lowers line losses and reduces maximum demand charges on your electricity bill.

Cost Savings

Improving PF from 0.72 to 0.99 can reduce reactive energy charges by up to 30–40%. Most electricity boards in India levy surcharges for PF below 0.90. Capacitor banks pay back their cost in months.

How We Calculate

Understanding Power Factor

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