Plan sprays, mists, or drips with confidence daily. Match nozzle diameter to your available pressure. Reduce runoff, save water, and improve plant coverage fast.
| Application | Shape | Dimensions | Target (mm/hr) | Nozzles | Pressure (bar) | Per-nozzle target (L/min) | Suggested nozzle |
|---|---|---|---|---|---|---|---|
| Spray | Circle | Radius 4.0 m | 8.0 | 4 | 2.5 | ~1.68 | Spray 1.5 mm (typical match) |
| Misting | Rectangle | 10 m × 5 m | 6.0 | 6 | 2.0 | ~0.50 | Mist 1.0–1.2 mm (fine coverage) |
| Drip | Rectangle | 6 m × 2 m | 10.0 | 8 | 1.2 | ~0.25 | Drip 0.9 mm (regulated flow) |
Examples are illustrative. Use manufacturer charts for final verification.
This calculator links a target precipitation rate (mm/hr) to the total flow rate (L/min) using the irrigated area. As a working reference, many gardens perform well around 5–15 mm/hr depending on soil texture, slope, and plant demand. Sandy soils often accept higher rates, while clay soils benefit from lower rates and longer run times.
Increasing the number of nozzles reduces the required flow per nozzle, which can improve coverage and reduce dry spots. For small zones, a few evenly spaced nozzles can outperform a single high-flow nozzle that creates run‑off near the source. Keep spacing consistent with the spray pattern and overlap recommendations from the nozzle manufacturer.
Pressure is converted to a pressure drop inside the nozzle and affects discharge through the orifice equation. Higher pressure generally increases flow and produces finer droplets, which can raise drift risk in wind. If your system includes filters, valves, or long hoses, measure pressure near the nozzle after those losses.
The discharge coefficient (Cd) captures real‑world effects like contraction and friction at the orifice. Typical small-nozzle values often fall between 0.55 and 0.65, while some regulated drip emitters behave differently. If you have a manufacturer flow chart, adjust Cd or pressure to match observed flow.
After selecting a nozzle size, verify distribution with a simple catch‑cup test and compare measured depth to the target. If measured precipitation is high, reduce pressure or add nozzles to share flow. If it is low, increase pressure within safe limits or select a larger diameter nozzle.
Start around 8–12 mm/hr for many mixed garden beds. Clay soils often need lower rates to prevent puddling, while sandy soils can accept higher rates with shorter cycles.
mm/hr is an intuitive watering intensity. The calculator converts it into flow using the irrigated area, then divides by nozzle count to give a realistic per-nozzle target.
It is a physics-based estimate that depends on pressure, diameter, water density, and Cd. Manufacturer charts are best for final selection, especially for specialty patterns or regulated emitters.
Overshoot can cause runoff and uneven wetting. Reduce pressure with a regulator, add more nozzles, or choose a smaller diameter. The oversize allowance helps you spot large mismatches.
Measure as close to the nozzle as possible. Filters, valves, quick couplers, and hose length can reduce pressure significantly, changing flow and spray characteristics.
Wind increases drift and breaks uniformity. Prefer larger droplets and lower spray height, avoid fine misting in strong wind, and irrigate during calmer hours like early morning.
Yes, for basic low-flow sizing and comparisons. Many drip emitters are pressure-compensating, so always validate with emitter specifications and consider adding regulators for stable performance.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.