Skip to main content

Generator Sizing Calculator

How to calculate the generator size required for the job?

How to size a generator?

Sizing a generator may seem to be a straightforward task: calculate the total power output of the equipment that you need to run, take into account the starting wattage (as it can be several times higher than the running wattage), convert this data to kW, and ensure that the generator can give you sufficient power, which is just above your maximum required power. 

There are various generator sizing calculators available on the web, and simple conversions below can help you too, if you are looking to roughly calculate what size generator you need.

Convert kVA / kW / HP 

*In the kVA to KW converter, 0.8 Power factor is typically used. However, this figure does vary depending on the installation that will be powered. If a leading power factor is onsite, please contact us to assist you with sizing.

Calculate electric current and kVA

All online calculators only provide a very rough estimate!

All online generator size calculators only provide a very rough estimate, which we recommend being taken as guidance only. If you are looking for power that is energy efficient, can save you fuel and reduce emissions as well as costs whilst reducing the chance of equipment breakdowns, let the specialists guide you.

Contact our generator rental specialists

Generator sizing done the Aggreko way

At Aggreko, we treat generator sizing as a complex task, and consider a broad range of factors, especially if you need to size industrial generators and are looking for an efficient solution. As a result, we may recommend multiple generators instead of one, a combination of a generator with a battery storage and other options. 

Below is a brief overview of factors influencing generator sizing. 

  1. Ambient temperature and altitude.
  2. Minimum generator load / capacity
  3. Application (standby, prime power, or in parallel; operation hours)
  4. Type of fuel (gas generators are often oversized; using alternative fuels, such as biofuel, adds to the complexity, but allows reduction of greenhouse gas emissions)
  5. Type of loads
  6. Peak power

Need to accurately calculate the generator size required?

Consult our generator sizing experts today