Generator Size Calculator
Add your equipment, account for motor surge loads and get a minimum kVA recommendation with fuel use estimate.
Track generators and site equipment against every asset — free.
Surge watts matter most
Electric motors need 2–3× their running watts to start. A 2.2 kW compressor can surge to 6.6 kW. Size your generator on surge, not running load.
kVA ≠ kW
Most generators are rated in kVA. At a power factor of 0.8, a 10 kVA generator delivers 8 kW of real power.
20% headroom built in
The recommendation includes 20% headroom above your peak surge load. Running a generator at full capacity continuously shortens its life.
Your Equipment
Add all equipment you may run simultaneously. Surge factor is set automatically for motor loads.
Generator Fuel Type
Results
Add your equipment and enter wattages to get a generator size recommendation.
Typical Fleet & Workshop Wattages
If you don't know your equipment's wattage, use these typical values as a guide.
| Equipment | Running Watts | Surge Factor | Peak Surge |
|---|---|---|---|
| Air compressor (2.2 kW) | 2200 W | ×3 | 6600 W |
| Water pump (1.5 kW) | 1500 W | ×3 | 4500 W |
| MIG welder (140A) | 4000 W | ×1.2 | 4800 W |
| Angle grinder (large) | 2300 W | ×2 | 4600 W |
| Vehicle lift motor (2.2 kW) | 2200 W | ×2.5 | 5500 W |
| Refrigerated unit | 3000 W | ×2.5 | 7500 W |
| Conveyor / auger (1.5 kW) | 1500 W | ×2.5 | 3750 W |
| Pressure washer (2.5 kW) | 2500 W | ×2 | 5000 W |
| LED floodlight (200W) | 200 W | ×1 | 200 W |
| Electric fan heater (3kW) | 3000 W | ×1.5 | 4500 W |
Running wattages are typical — check your equipment nameplate for the actual figure. Surge factors are approximate; motor size, age and condition all affect starting current.
Frequently Asked Questions
Track Every Generator & Asset in One Place
FleetBolt lets you store key specs against every vehicle and machine, free to get started.
Get Started Free