Pump Curve Point Calculator for Garden Systems

Calculator Inputs

Choose a method, enter points, then calculate.

Garden irrigation sizing

Method

Pick based on the curve data you have.

Flow unit

Head unit

Point 1 flow (Q1)

Point 1 head (H1)

Point 2 flow (Q2)

Point 2 head (H2)

Point 3 flow (Q3)

Point 3 head (H3)

Target flow (Qt)

Target head (Ht)

Ratio (r)

Use N2/N1 or D2/D1, depending on choice.

Scaling type

Reset

Tip: For garden systems, measure head at a few flows using your pump chart or test bucket data, then fit a curve to estimate operating points across sprinklers and drip zones.

Example Pump Curve Data Table

Sample values for demonstration. Replace with your pump’s data.

Flow (Q)	Head (H)	Notes
40 L/min	18 m	Higher head for small zones.
60 L/min	14 m	Typical mixed sprinkler demand.
80 L/min	9 m	Lower head at higher flow.

If you use pressure units (kPa), convert head consistently before comparing.

Formulas Used

Quadratic pump curve fit: H = aQ² + bQ + c (fits three points exactly).
Linear interpolation: H = H1 + m(Q − Q1), where m = (H2 − H1)/(Q2 − Q1).
Affinity scaling: Q2 = Q1·r and H2 = H1·r², where r is a ratio.
Flow from head (quadratic): solve aQ² + bQ + (c − Ht) = 0.

These methods estimate pump behavior; always confirm critical designs with manufacturer curves and system losses.

How to Use This Calculator

Select a method based on how many curve points you have.
Choose units so all entries stay consistent.
Enter curve points from a chart, datasheet, or field test.
Provide a target flow to estimate head at that flow.
Optionally provide a target head to estimate flow for that head.
Click Calculate to view results above the form.
Use CSV or PDF buttons to export the computed report.

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