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

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

Appliance	Running watts	Starting (surge)
Circular saw (7-1/4 in)	1,500	4,200
Miter saw (10 in)	1,800	—
Air compressor (1 HP)	1,600	4,800
Electric drill (1/2 in, 5.4 A)	600	900
Angle grinder	800	2,400
Quartz halogen work light (300-1000 W)	1,000	—
Power-tool battery charger	380	—

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

Wattage Worksheet '3R0WATTGUIDE' (generator reference guide, Home Depot-hosted PDF) (vendor)
A-iPower Wattage Chart (Sam's Club-hosted PDF) (vendor)
Champion Power Equipment 'Choosing a Generator' wattage flyer (manufacturer)
Milwaukee 48-59-1808 M18/M12 Rapid Charger operator's manual (PDF) (manufacturer)
Grounded Electric generator wattage chart (licensed electrical contractor) (vendor)

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