Generator Sizing Tool
Technical sizing for field engineers — estimate running load and peak start surge from motors, breakers or known power requirements before an installation.
Built for technicians, engineers and installation teams who need a fast, defensible estimate on site.
Loads
Recommended Size
Estimate only — running load × 1.25 headroom vs. peak load × 0.9 (generators tolerate brief overload on motor inrush). Always confirm with manufacturer derating tables and site conditions before final selection.
OnCaire field engineers get sizing, dispatch and fleet data in one platform — built for installation and service teams.
See Service PlatformHow the estimate works
A field-ready model that combines steady-state demand with motor inrush — the two numbers that actually decide generator size.
List your loads
Add each load as a motor (HP), a breaker (amps & voltage) or a known running power (kW). Set quantities for repeated units.
We compute running & peak
Running load sums steady-state demand. Peak load adds the single largest starting surge — the realistic worst case for inrush.
Get a sized recommendation
The tool sizes for running load with headroom and for peak load with short-term overload tolerance, then rounds up to a safe kW rating.
Sizing is one part of the job
See how OnCaire connects sizing, dispatch, tickets and fleet data for service and installation teams.
See Service Platform