Power Factor Correction & Payback Calculator

A power factor correction tool that estimates required capacitor kVAR and the practical benefit of improving power factor.

Last updated: July 27, 2026

Inputs

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Formula logic, use cases, assumptions, and limits for this tool.

How this tool helps

Use this to estimate capacitor bank size and whether power factor correction has a commercial payback.

Assumptions and limits

This tool provides a planning-level result. It does not replace detailed engineering design, approved software, manufacturer data, authority requirements, or project specifications.

Typical use cases

  • Early estimation and tender support.
  • BOQ sanity checking and technical review.
  • Site discussion before final engineering verification.
  • Comparison of alternatives using consistent assumptions.

Result interpretation

Read the recommendation, warning, and confidence sections together. A result without warnings is still not an approval; it only means the entered values did not trigger built-in planning alerts.

Input definitions and typical values

These notes explain what each input means and which values usually produce a more reliable planning result.

Active power kW

Load or power in kW. Use realistic running or design demand, not inflated connected load unless the tool asks for connected load.

Current power factor

Electrical current or battery input. Use measured standby/alarm current or manufacturer datasheet values for better results.

Target power factor

Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.

System voltage V

System voltage. Common LV systems include 230 V single-phase and 400/415 V three-phase; use project nominal voltage.

Estimated monthly saving currency/month

Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.

Capacitor installed cost currency/kVAR

Project input used directly in the calculation. Use measured, scheduled, manufacturer, or authority-approved values where available.

Practical verification checklist

  • Confirm the selected standard profile is suitable for the project location and authority.
  • Replace sample values with project drawings, schedules, equipment data, or measured site values.
  • Review warnings, methodology, and PDF report before using the result outside early planning.
  • Verify final decisions against official standards, manufacturer data, consultant specifications, and local approvals.

Calculation methodology

Required kVAR = kW x (tan acos current PF - tan acos target PF). kVA relief and simple payback are estimated.

Inputs are treated as planning assumptions. The calculator shows warnings when entered values fall outside practical thresholds or selected standard-profile limits.

View full methodology notes

Version history

  • v1.3.6-prelaunch: Added methodology, standard profile support, version notes, and direct PDF report download.
  • v1.3.5: Calculator page added with sample data, warnings, and print-ready report layout.

Stage 2 roadmap: optional saved projects, dashboards, and shared calculation history without forcing login for free use.

Trust and verification

Every result includes assumptions, warning logic, and a downloadable report. Final engineering decisions still need qualified review, local authority approval, manufacturer data, and project specifications.

Worked example

Use the sample data button to load a realistic scenario, then download the PDF report to review inputs, results, methodology, warnings, and disclaimers in one place.