What Size Generator Do You Need for a Job Site? (Tool Chart)

Wattage data last verified 2026-08-28 · every wattage cites its source · methodology

Running a job site — everything in the sourced list below at once — takes about 7,680 running watts with 10,880W available at startup (the largest motor's surge). With 20% headroom, look for a generator rated around 13,100W; drop items from the list and the number falls fast.

The list, with sourced watts

ApplianceRunning wattsStarting (surge)
Circular saw (7-1/4 in)1,5004,200
Miter saw (10 in)1,800—
Air compressor (1 HP)1,6004,800
Electric drill (1/2 in, 5.4 A)600900
Angle grinder8002,400
Quartz halogen work light (300-1000 W)1,000—
Power-tool battery charger380—
Running watts versus starting surge, per appliance Horizontal bars for 7 appliances. The solid bar is running watts; the lighter extension is the extra the motor briefly demands at startup. Circular saw 1,500 running, 4,200 starting. Miter saw 1,800 running. Air compressor 1,600 running, 4,800 starting. Electric drill 600 running, 900 starting. Angle grinder 800 running, 2,400 starting. Quartz halogen work light 1,000 running. Power-tool battery charger 380 running. running watts extra at startup Circular saw 1,500 → 4,200W Miter saw 1,800W Air compressor 1,600 → 4,800W Electric drill 600 → 900W Angle grinder 800 → 2,400W Quartz halogen work light 1,000W Power-tool battery charger 380W
The startup surge is the part a generator has to cover but a spec sheet rarely leads with — here the air compressor (1 HP) briefly demands 3,200W more than it runs on. Same figures as the table, each cited on the methodology page.

The arithmetic

Running total: 7,680W
+ largest single starting surge: 3,200W
= peak demand: 10,880W
× 1.2 headroom → recommended rating: ~13,100W

Generators that cover this (from our verified catalog)

Westinghouse WGen14500DFc
14,500W rated · 18,000W starting · dual fuel (gasoline/propane)
Spec: manufacturer

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Generac Guardian 26kW (7290)
22,500W rated · natural gas / liquid propane (standby)
Spec: manufacturer

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Adjust this list in the calculator →

What size generator do I need for a job site?

7,680 running watts with 10,880W at startup for the full list — ~13,100W rated with headroom. Trim the list to shrink the requirement.

Why do starting watts matter?

Motor-driven loads briefly draw 2–4× their running watts at startup. Cover the running total plus the single largest surge, or the motor stalls.

Is a bigger generator always better?

No — oversized open-frame units burn more fuel and run louder. Size to your real list with ~20% headroom.

Sources

Figures are conservative sizing values chosen from the range these sources report. Your appliance's nameplate is authoritative.