Pump & Irrigation Flow Rate Calculator

Pump & Irrigation Flow Rate Calculator

Size irrigation and recirculation pumps with confidence. Plan emitter flow, estimate Total Dynamic Head (TDH), and get the minimum pump GPH/LPH needed. Prefer help? Talk to a Grow Expert.

Shop Water Pumps Open Calculator Drip Irrigation Guide

Irrigation & Pump Sizing

Choose a mode: Emitter Sizing, Pump Sizing, or Tubing & Head Loss.

Tip: For drip irrigation, size for the instantaneous flow while valves are open, not daily volume. Add a safety margin for pump wear and filters.
Common drippers: 0.5, 1.0, 2.0 GPH (≈2, 4, 8 LPH).

Frequently Asked Questions

What is Total Dynamic Head (TDH)?

TDH is the vertical lift (static head) plus friction losses in tubing and fittings, converted into equivalent feet (or meters) of head. Pumps are rated by how much flow they deliver at a given head.

How much safety margin should I use?

10–30% is common. Use more if your system has fine filters, long runs, many fittings, or if you want quieter operation.

How do I pick emitter size?

Start with 0.5–1.0 GPH (≈2–4 LPH) for smaller containers, and 1–2 GPH (4–8 LPH) for larger. Increase emitters per plant to improve distribution.

Recirculating vs. irrigation pumps?

Recirculating pumps run continuously and typically target 2–4 tank turnovers per hour. Irrigation pumps run intermittently and should be sized for the instantaneous demand while valves are open.

How accurate is the friction model?

We use a simplified Hazen‑Williams approximation suitable for cold water and common horticulture flow ranges. Always verify with your actual pump curve and adjust if needed.