Online Hydraulic Calculators
A collection of free online hydraulic calculators for fire protection and water mist engineers. Use these tools to quickly check calculations, verify unit conversions, and explore hydraulic relationships — no software installation required. For full system hydraulic design, take a look at FHC, our professional hydraulic calculation software used by engineers in over 60 countries
K-Factor Calculator
Free online K‑factor calculator allows fire sprinkler and water mist design engineers to quickly calculate flow rate, pressure, or K‑factor for sprinkler heads and nozzles
Hazen-Williams Calculator
Hazen-Williams calculator, which you can use to calculate the pressure loss in a pipe
Pipe Velocity Calculator
Looking to calculate the velocity in a pipe or determine the diameter of a pipe
Pressure & Flow Convertor
Convert pressure and flow rate units instantly. Bar, psi, kPa, metres head, litres per minute, litres per second, m³/h and US gal/min.
Further reading
If you found these tools useful, the following pages may also be of interest. Our hydraulic calculations overview covers the principles behind fire protection hydraulics, and our resources page includes supporting downloads and reference material. For articles on fire protection engineering topics, visit the Learning Hub, where you will find guides and technical content to support your design work. Engineers looking to move beyond manual checks can evaluate FHC, our professional hydraulic calculation software for fire sprinkler and water mist system design.