Calculating Hydro Power

How to calculate Hydroelectric power

Knowing how to calculate hydroelectric power using head and flow figures from your site is key to the viability of your hydropower system.

The calculator below can help you determine roughly how much power output your site could provide. If you know the head and flow at your site then enter them into the calculator and check your sites results.

For guidance on how to estimate the head and flow at your site please use our guides.

The equation used to calculate how much power can be generated from a site is:

Power = Density x Gravity x Head x Flow x Efficiency


If you are considering a Hydro project and believe that your watercourse has sufficient Head and Flow then please get in touch to discuss how we can help.


If you have performed calculations and believe that you have a viable site for a Hydropower system, it is important to remember that the design of a hydroelectric system is bespoke as no two sites are the same. Variants including the intake structures, pipe work, turbine house and tail race, can all effect the power output. This simply means it is important to have accurate figures at this early stage to avoid being knocked back at a later date. It is not just about knowing how to calculate hydroelectric power, but also understanding the amount of preliminary and construction work the project will entail.

Talking to us early on can help. Another important consideration is that construction areas are often within a running river and more often than not, they are in remote locations.  These variants combined can be overwhelming for those that are new to Hydro systems, so experience and engineering know-how are essential to ensure system installations are robust and cost effective. Each aspect has to be carefully considered and experience over the range of engineering disciplines is essential to ensure systems perform well, for life.

Harness the power