Transfer Switch Sizing Calculator

Find the right transfer switch for your generator backup system. Enter your generator size, panel amperage, and backed-up load to compare manual and automatic switch options with installed pricing.

Generator & Panel

Generator Size (watts)

Total Backed-Up Load (watts)

Circuits to Back Up

Service Panel Size

Switch Type

Pricing (edit to match local rates)

30A Manual 6-ckt ($)

50A Manual 10-ckt ($)

100A Automatic ($)

200A Automatic ($)

Installation Labor ($)

Generator Output

31.3A

7,500W at 240V

Backed-Up Load

20.8A

5,000W across 6 circuits

Recommended

30A Manual (6-circuit)

$1,550.00 installed

Purchase Option	Quantity	Est. Cost
30A Manual (6-circuit)Best value	30A / 6 circuits	$1,550.00
50A Manual (10-circuit)	50A / 10 circuits	$1,750.00

Recommended: 30A Manual (6-circuit) ($1,550.00 installed)A 30A manual transfer switch is the most affordable option for backing up a small number of essential circuits. You will need to manually start the generator and flip the switch during an outage.

Nearing the circuit limit on the 6-circuit switchYou are backing up 6 of 6 available circuits. If you need to add more circuits later, consider the 50A 10-circuit manual switch for flexibility.

This is a sizing estimate only. Transfer switch selection depends on local electrical codes, panel configuration, and generator compatibility. Always consult a licensed electrician before purchasing and installing a transfer switch.