---
title: "Power Factor Calculator"
canonical: "https://ampstowatt.com/power-factor/"
author: ""
published: "2026-09-05T09:07:26+00:00"
modified: "2026-09-05T09:07:26+00:00"
language: "en-US"
site: "Ampstowatt"
description: "Calculate power factor from watts and VA. Find kVAR for capacitor sizing. Supports single-phase and 3-phase AC power calculations."
attribution: "Ampstowatt (https://ampstowatt.com/)"
---

# Power Factor Calculator

Power quality

 PF = Watts ÷ Volt-Amps            

## Power Factor Calculator

 

Calculate power factor from real watts and apparent volt-amps.

  

Live Result

  ✓
 Formula-backed — instant professional result       REAL POWER W  

W

  APPARENT POWER VA  

VA

       POWER FACTOR    0   PF    Also equals **0 %**    Formula used  PF = Watts ÷ Volt-Amps   Power factor shows how much apparent power becomes usable real power.   800W ÷ 1000VA = 0.80 PF           

This calculator is an educational planning estimate. Verify safety-critical work with equipment nameplate data, local electrical code, and a qualified professional.

     

Calculate power factor from watts and VA. Find kVAR for capacitor sizing. Supports single-phase and 3-phase AC power calculations.

    

AC power quality

 

## Power triangle clarity

 

Calculate power factor from watts and VA. Find kVAR for capacitor sizing. Supports single-phase and 3-phase AC power calculations.

  AC/DC single-phase formula-first page-specific visual     5 kVA at PF 0.80 **4,000 W**   VA  PF  W   working formula **PF = Watts / VA** *Real watts separated from VA, kVA, and power factor for AC equipment.*   Real powerApparent powerPFSurge load       GUIDE 

## Power Factor Calculator — Real, Apparent & Reactive Power | Ampstowatt Guide

      

Real vs apparent power

 

## Watts, VA, kVA, and power factor shown as one relationship

 

These conversions depend on the difference between real and apparent power, so the power triangle makes the formula easier to trust.

  Formula **PF = Watts / VA**   
***Power Factor Calculator — Real, Apparent & Reactive Power | Ampstowatt** Real vs apparent power with real formula values and planning checkpoints.*
     

Quick answer

 

### Use this calculator to separate real watts from apparent power.

 

AC equipment can draw VA or kVA that is higher than usable watts. Power factor explains the difference and is critical for generators, UPS systems, motors, and transformers.

 PF = Watts / VA   

### Inputs to check before calculating

 

- Use nameplate VA, kVA, or amperage where available.
- Enter a realistic PF for motors, compressors, UPS systems, and generators.
- Account for startup surge separately from running watts.
- Compare real watts with equipment output ratings.

   

### Example: real power vs apparent power

 

If equipment uses 800 W from 1,000 VA, the power factor is 0.80. Use that value when converting AC amps to watts or watts to amps for motors, HVAC, and generators.

   

### Best use cases

 

- Real vs apparent power
- Current estimate
- PF quality band
- single-phase AC load planning with clear unit labels.

   

### Common mistake to avoid

 

Do not treat kVA as kW unless the power factor is 1.00.

   

### How to use the result

 

Use the result to avoid undersizing generators, UPS units, and AC power equipment.

   **Accuracy and safety note** 

Calculator output is a planning estimate. Final breaker sizing, wire
 gauge, derating, voltage-drop limits, equipment protection, and code
 compliance should be verified with manufacturer documentation and a
 qualified electrician or engineer.

 

For the broad formula, reference table, and breaker planning context,
 start with the [main Amps to Watts Calculator](/).

        Technical Diagram 

## Power Factor Calculator Formula Map

 

**PF = W / VA**

 

VA = apparent power, W = real power. Use the calculator on this page to change the inputs and verify the result before sizing equipment.

        Hub  

## Apply This Knowledge

     **Start with the main conversion tool** 

Use these calculator pages to apply the concept to real current, voltage, watts, and power-factor problems.[Amps to Watts Calculator](/)

  [W**Amps to Watts Calculator**Main calculator hub and formula reference](/)[AC**AC Amps to Watts Calculator**Apply power factor to AC current](/ac-amps-to-watts-calculator/)[DC**DC Amps to Watts Calculator**Use the direct DC watts formula](/dc-amps-to-watts-calculator/)[A**Watts to Amps Calculator**Find current from known watts and volts](/watts-to-amps-calculator/)[FX**Amps to Watts Formula**Review the formulas behind the tools](/amps-to-watts-formula/)[TAB**Conversion Charts**Compare common amp, volt, and watt values](/conversion-charts/)     Advertisement