Inputs
Use realistic nozzle sizes and pipe diameters for stable spray patterns.
Formula used
This model is a practical estimate for garden fountains.
- v = √(2 g H) — nozzle exit velocity for target jet height.
- Q = A · v — nozzle flow rate (A = π d²/4).
- h_f = f (L/D) (v²/2g) — Darcy–Weisbach friction head.
- h_m = K (v²/2g) — minor losses from fittings.
- H = lift + Hjet + h_f + h_m — total dynamic head.
- P = ρ g Q H and P_in = P/(η) — hydraulic and input power.
How to use this calculator
- Measure lift from water surface to the nozzle.
- Choose your desired jet height and nozzle diameter.
- Enter pipe length, inner diameter, and fitting counts.
- Set efficiency and a safety margin for real-world losses.
- Click Calculate, then pick a pump by its performance curve.
- Download CSV or PDF for your quote or install notes.
Example data table
Sample numbers are illustrative. Always verify with the pump’s curve chart.
| Scenario | Jet height | Nozzle | Pipe | Fittings | Recommended flow | Recommended head |
|---|---|---|---|---|---|---|
| Small patio bowl | 1.0 m | 1 × 8 mm | 2 m, 16 mm | 2×90°, 1 valve | ~1,800 L/h | ~2.2 m |
| Courtyard feature | 1.5 m | 1 × 10 mm | 4 m, 20 mm | 4×90°, 1 check | ~3,500 L/h | ~3.6 m |
| Two-nozzle display | 1.2 m | 2 × 8 mm | 5 m, 25 mm | 6×90°, 1 tee | ~3,600 L/h | ~3.0 m |