Count stations for valves, pumps, and zones. Match controller limits, module steps, and spare planning. Design a tidy irrigation plan that grows with you.
| Scenario | Existing | Future | Spare % | Max/controller | Master | Suggested |
|---|---|---|---|---|---|---|
| Backyard refresh | 8 | 2 | 15% | 24 | Yes | 1 controller, 12 stations |
| Large landscape | 26 | 6 | 20% | 32 | Yes | 2 controllers, 20 stations each |
| Small garden | 4 | 0 | 10% | 8 | No | 1 controller, 4 stations |
Examples are illustrative; your results depend on module increment and redundancy settings.
1) Raw stations needed
Raw = Existing zones + Future zones + Master station (if selected)
2) Stations required with planning headroom
Required = ceil(Raw × (1 + Spare% ÷ 100)) + Redundancy
3) Controllers needed
Controllers = ceil(Required ÷ Max stations per controller)
4) Suggested station capacity per controller
Size each = max(Base, ceil((Required ÷ Controllers) ÷ Increment) × Increment)
Accurate station counts keep gardens healthy while protecting pumps, pipes, and budgets. Each station usually represents one valve-controlled zone with similar plant water needs and similar flow demand. Underestimating stations forces late add‑ons, extra wiring, and controller swaps. Overestimating can oversize equipment and inflate costs. This calculator translates your zone plan into a controller and module strategy with a growth buffer. It supports consistent scheduling across seasons today.
Start by mapping planting beds, turf, and containers, then group areas by sun exposure, soil texture, and emitter type. Check available flow at the point of connection and allocate it across zones so each zone stays within safe flow and pressure limits. If you mix drip and spray, count them as separate stations. The base station input is your best current design.
Controllers have a maximum station capacity, and many support expansion modules that add stations in fixed increments. The calculator compares your required stations to the preferred maximum per controller and recommends how many controllers you need. It also estimates how many expansion modules are required when you choose a modular style. This helps you plan enclosure space, power, and wire terminations.
Some irrigation designs reserve a master valve or pump start output. When enabled, the calculator adds that output to the station requirement so you do not run short during commissioning. A spare percentage adds capacity for future beds, repaired valves, or seasonal adjustments. Typical allowances range from 10–25% depending on how fast the garden is expected to change.
Use the recommended station total to confirm wire counts, common wire sizing, and terminal labeling. The controller count supports cost estimating and procurement, while the module count supports phased upgrades. Export the CSV for a bill‑of‑materials worksheet and the PDF for client approvals and crew handoffs. Recalculate whenever zones change or flow testing updates your plan.
Count one station per valve-controlled zone. Separate drip, spray, and rotor areas into different zones, and split long beds if pressure loss is high. Use your current irrigation plan or a field layout sketch as the base.
Spare percent increases required capacity to cover future beds, replacement valves, and design tweaks. For stable gardens, 10% is common. For expanding landscapes or new sites, 15–25% helps avoid running out of terminals.
Enable it when your system uses a master valve or pump start output that occupies a controller terminal. If your controller provides a dedicated pump output that does not reduce station terminals, leave it off.
It reflects your preferred limit per controller for wiring simplicity, cabinet space, and troubleshooting. Even if a controller can handle more, you may choose fewer stations per unit to reduce long wire runs and crowding.
When modular mode is selected, the calculator rounds up the stations needed beyond the base unit to the module increment you enter. This mirrors real modules that add fixed station blocks, ensuring you purchase enough capacity.
CSV is ideal for editing quantities, costs, and notes in spreadsheets. PDF is better for sharing a fixed plan with clients and installers. Both keep your controller sizing decisions documented for future maintenance.
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.