BACKUP POWER, WITHOUT THE GUESSWORK

RV Generator Size Calculator

Choose generator capacity for the way you travel. Add your RV service, air conditioner, and appliances to estimate running power and starting demand, then compare different load combinations.

Service describes your connection, not your actual load. Downstream DC appliances are covered by the converter and must not be added twice.

MAKE IT YOUR SETUP

Your loads 3

Changes update your result
Qty1
Details & exact specs
Running
725 W
Starting
725 W
Voltage
120 V
Qty1
Details & exact specs
Running
252 W
Starting
252 W
Voltage
120 V
Qty1
Details & exact specs
Running
900 W
Starting
900 W
Voltage
120 V

Start with typical values. Fine-tune any appliance with its exact specifications.

Heat pumps or whole-home systems?

These can include outdoor units, air handlers and auxiliary heaters. They need a whole-system review.

SMALL CHANGES. LESS DEMAND.

Ways to reduce the size you need

These actions change your selected loads. They never change the calculation assumptions.

THE METHOD, MADE SIMPLE

Running power.
Starting headroom.

We add the running watts of your enabled appliances, then allow for the largest single motor startup. The running recommendation includes a 20% operating reserve.

Example: a 200 W refrigerator with 1,200 W starting power needs 250 W recommended running capacity and 1,200 W starting capability when used alone.

01Add your running loadsWatts × quantity for each enabled appliance.
02Allow for one motor startingThe largest additional startup, one unit at a time.
03Leave operating headroomRunning load ÷ 0.80, rounded up.

Power safely. Every time.

Never run a portable generator indoors, in a garage, or near openings. Do not backfeed a home electrical system. Have transfer equipment installed according to applicable electrical rules.

A few useful things to know

Are starting watts added for every appliance?

No. This model assumes one motor starts at a time while the other selected loads are running. Simultaneous startup needs a separate assessment.

Can I enter amps or use LRA?

Use real input watts. Voltage × current is apparent power (VA), not real watts without a known power factor. LRA is not a direct starting-watts value.

Where do the values come from?

Values come from the reviewed BGT 1.2.2 dataset. Open a load’s source details for manufacturer and planning references. Estimates and exact overrides remain clearly labeled.

1,222 W runningPeak 977 W · 120V
View result ↑

Result: 1,222 watts running, 977 watts starting.