Watering Calculators: Delivery, Reservoir & Gravity

Pot & Drip information page · About the publication

Estimate what a system delivers before deciding what your plants need.

These tools calculate nominal quantities, not irrigation prescriptions. Actual flow, growing medium, weather and plants determine a useful schedule.

Nominal water delivery

Enter values and calculate.

Reservoir planning

Enter values and calculate.

Gravity-fed static pressure

Enter values and calculate.

Formulas and limits

  • Total GPH = emitter count × rated GPH per emitter. Gallons per cycle = total GPH × minutes ÷ 60.
  • Reservoir gallons = measured daily gallons × days × (1 + reserve percentage ÷ 100). Use actual usable capacity.
  • Static head in PSI ≈ water height in feet ÷ 2.31. This excludes friction and component losses.

For mixed emitter rates, calculate each group separately and add the results. Reserve is a planning assumption, not a guarantee. Check manufacturer operating ranges; these tools do not validate tubing capacity or minimum operating pressure.

Read the container guide, gravity guide and pressure regulator guide to understand the assumptions behind these estimates.

Privacy: the calculations run in your browser and do not send the entered values to Pot & Drip.

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