Generator Size Calculator.

A typical home needs 5,000-7,500 running watts. Select your appliances above to get a personalized estimate including surge watts.

Yes, with a 20-26 kW standby generator. Select all your appliances above — the calculator shows what size is needed for full coverage.

5,000-7,500W for essentials, 15,000-20,000W+ for whole house. Check appliances above and the running watts update live.

Central AC needs 3,500-6,000 surge watts. A 10-12 kW generator handles HVAC plus essential circuits. Check HVAC in the calculator above.

Add running watts + highest surge watt. The calculator does this automatically — just check the appliances you need during an outage.

Surge watts are the extra burst motors draw when starting (2-3x running watts). The calculator accounts for the highest surge demand.

Running watts is the continuous power appliances need. For non-motor loads (lights, heaters) it equals surge. The calculator shows both.

Portable units (3-12 kW) power essential circuits but not whole-house HVAC usually. Select only essentials above for portable sizing.

Add ~20% buffer to your calculated needs. The calculator rounds up to the next standard generator size for safety margin.

Yes, but a Level 2 charger draws 7,200W+. Most portable generators can't sustain this. A 20kW+ standby generator is recommended for EV charging during outages.