Output has to cover what starts as well as what runs. A motor draws far more current at the moment it starts than while it turns, so a generator sized to the running figure will trip or stall when the tool is switched on. Allowing headroom over the running figure is what keeps a generator working rather than cutting out.
Inverter or conventional decides what the generator can safely power. An inverter generator produces a clean, stable output suitable for electronics and chargers. A conventional generator is cheaper per kW and fine for lighting, heating and motors that do not care about waveform. Waveform is stated per machine rather than being implied by the price or the output.
Fuel follows how long the machine runs and where. Petrol machines are lighter and start easily. Diesel machines run longer per tank and are the usual choice for extended site use, with silenced forms where noise matters. Clarke run petrol machines from 2.7kVA to 6.5kVA with inverter generators at 2.2kW, 3.8kW and 7.5kW.
Supply voltage matters on site. Dual voltage machines give 230V and 110V from the same generator, which removes the need for a transformer alongside it. Electric start and long run tanks reduce the attention the machine needs during a shift. List the tools that will run at once, with their starting figures, and send it to 07754288583 on WhatsApp for a size. Silenced diesel machines cover site work where the generator runs beside people all day.