Every sprinkler hydraulic calculation starts with one relationship: the flow out of a head grows with the square root of the pressure behind it. Use this calculator to get the flow from a known pressure, the pressure you need for a given flow, or the end-head flow from your design density and the area each sprinkler covers.
How to use it
- Pick the K-factor printed on the sprinkler data sheet (SI and US pairs are listed together).
- Choose what you know: pressure, required flow, or density and coverage area.
- For the most remote (end) sprinkler, use the density × area tab: the tool also applies the 0.5 bar (7 psi) minimum operating pressure.
- Carry the end-head flow and pressure into your pipe friction calculation, node by node, back to the riser.
Step-by-step guides
- Sprinkler Hydraulic Calculation: A Step-by-Step Worked Example
- Sprinkler Hazard Classification: LH, OH1, OH2, EH1 and EH2 Explained
- Sprinkler Spacing Rules: Areas, Wall Distances and Obstructions
More free tools
- Sprinkler Hydraulic Calculator — Full Remote-Area Calculation
- Hazen–Williams Pipe Friction Loss Calculator
- MEP Unit Converter — kW, BTU/h, TR, CFM, L/s, bar, psi
- All free MEP calculators
- MEP Library
Results are for preliminary design and checking. Always confirm against the standard edition and local regulations that apply to your project.
Online course · certificate included
Fire Protection & Suppression Systems Design (NFPA)
20 narrated modules with animated diagrams, two complete worked projects (DWG + DXF), the Fire Calc Workbook and an online calculator.
Modules 1–3 are free, no account needed · full course €15,00 one-time