1. What is a Generator Size Calculator?

Definition: This calculator determines the appropriate generator size in kilowatts (kW) based on your total electrical load and a safety factor.

Purpose: It helps homeowners, contractors, and businesses select the right generator capacity for their power needs.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( P_{kW} \) — Required generator size (kilowatts)
• \( \sum P_{load} \) — Sum of all electrical loads (watts)
• \( SF \) — Safety factor (typically 1.2-1.5)

Explanation: The total wattage is converted to kilowatts (divided by 1000) then multiplied by a safety factor to account for startup surges and future expansion.

3. Importance of Proper Generator Sizing

Details: Correct generator sizing ensures reliable power supply, prevents overloads, improves fuel efficiency, and extends equipment life.

4. Using the Calculator

Tips:

• Add up wattage of all devices you want to power simultaneously
• Use safety factor 1.2 for residential, 1.3-1.5 for commercial/industrial
• For motor loads, use starting wattage not running wattage

5. Frequently Asked Questions (FAQ)

Q1: What's a typical safety factor?
A: Residential: 1.2-1.3, Commercial: 1.3-1.5, Industrial: 1.5 or higher depending on load type.

Q2: How do I find my total load wattage?
A: Check appliance labels, manuals, or use our Load Calculator tool. For motors, use starting wattage.

Q3: Should I round up the generator size?
A: Yes, always round up to the next standard generator size (e.g., 5.3 kW → 6 kW unit).

Q4: What about three-phase power?
A: This calculator is for single-phase. For three-phase, multiply result by √3 (1.732).

Q5: Does this include future expansion?
A: Increase safety factor (e.g., 1.5) if planning to add more loads later.