Home Generator Size Calculator
Calculate the generator size needed to power essential home loads
About this calculator
The Home Generator Size Calculator helps homeowners determine the appropriate generator capacity needed to power essential appliances and systems during power outages. By calculating your home's power requirements, you can avoid purchasing an undersized generator that won't meet your needs or an oversized unit that wastes money on unnecessary capacity. This tool ensures you select the right generator size for reliable backup power when you need it most.
How to use
Enter the wattage requirements for each essential appliance or system you want to power during an outage, such as refrigerator, heating/cooling, lights, and electronics. The calculator will sum your total power needs and recommend the minimum generator size required, typically adding a safety margin for optimal performance.
Frequently asked questions
What's the difference between starting and running watts?
Starting watts are the initial power surge needed to start motors and compressors, while running watts are the continuous power required during normal operation.
Should I size my generator for all appliances?
Focus on essential items like refrigeration, heating/cooling, lights, and critical electronics rather than powering your entire home to keep costs reasonable.
How much safety margin should I add?
Add 20-25% extra capacity above your calculated needs to account for power fluctuations and potential future additions to your essential load list.