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What size generator do I need to run a circular saw, air compressor, and job site lights?

Running power tools and a compressor off one generator is common on sites without utility power, but the starting loads stack up fast. A circular saw and a 1 HP compressor both pull hard the moment they kick on, and if they start at the same time the generator will either stall or trip its breaker. Getting the sizing right means you can work without interruptions.

The load

SIZING PLATE3 LOADS · +25% HEADROOM
Total running watts
2,930 W
Peak (largest start)
4,430 W
Buy at least
3,700 W rated
Look for ~3,700W running / 4,450W surge or better.

Field note: Start your air compressor first and let it fully charge the tank before you pick up the saw — never run both motors simultaneously if you can avoid it. If your workflow requires the compressor cycling while you cut, look for a generator with a surge headroom rating rather than just a running-watt spec, since that cycling overlap is where undersized units fail. LED site lights draw almost nothing, so factor those in last; they will not meaningfully change your generator selection.

Right size: Mid-size portable (6,500W / 8,100W surge)

Typical price $700-1,200 · e.g. Westinghouse WGen6500, Champion 6250, Generac GP6500

Storm essentials with margin: fridge, freezer, sump pump, furnace fan, well pump (240V models), lights and electronics together. Louder open-frame design; electronics prefer models with THD under 5% or an inverter.

See current prices on Amazon

One size up: Large portable (9,500W / 12,500W surge)

Typical price $1,000-1,800 · e.g. Westinghouse WGen9500DF, DuroMax XP13000EH, Champion 12.5kW tri-fuel

Most of a house through an interlock kit: well pump, multiple large appliances, even a smaller central AC with a soft-starter. Heavy (200+ lbs), thirsty, and loud — this is serious-outage equipment, not camping gear.

See current prices on Amazon

Adjust for your setup

Different fridge? Bigger AC? Uncheck and re-check below — the plate recomputes live.

SIZING PLATE3 LOADS · +25% HEADROOM
Total running watts
2,930 W
Peak (largest start)
4,430 W
Buy at least
3,700 W rated
Look for ~3,700W running / 4,450W surge or better.

Peak assumes your largest motor starts while everything else runs — the honest worst case. Start big motors one at a time and a smaller unit may cope, but this number won't let you down.

Kitchen
Heating & cooling
Pumps & well
Electronics
Medical & safety
Lighting
Laundry
Household
Tools & outdoor
RV & camping

Generators that fit

Right size: Mid-size portable (6,500W / 8,100W surge)

Typical price $700-1,200 · e.g. Westinghouse WGen6500, Champion 6250, Generac GP6500

Storm essentials with margin: fridge, freezer, sump pump, furnace fan, well pump (240V models), lights and electronics together. Louder open-frame design; electronics prefer models with THD under 5% or an inverter.

See current prices on Amazon

One size up: Large portable (9,500W / 12,500W surge)

Typical price $1,000-1,800 · e.g. Westinghouse WGen9500DF, DuroMax XP13000EH, Champion 12.5kW tri-fuel

Most of a house through an interlock kit: well pump, multiple large appliances, even a smaller central AC with a soft-starter. Heavy (200+ lbs), thirsty, and loud — this is serious-outage equipment, not camping gear.

See current prices on Amazon
This site earns commissions from qualifying purchases made through links to Amazon and other retailers, at no extra cost to you. Wattage figures are typical estimates — actual draw varies by model. Always verify against your appliance's nameplate, and consult a licensed electrician for any panel or hardwired connections.