Water Feature Pump Calculator
Size a pond or fountain pump in GPH. Enter water volume, turnover rate, and head height to find the correct pump plus tubing size and energy cost.
gal
ft
Required GPH
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Rated GPH (at head) —
Recommended Tubing —
Extended More scenarios, charts & detailed breakdown ▾
gal
ft
Required GPH
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Buy Pump Rated (GPH) —
Tubing Size —
Professional Full parameters & maximum detail ▾
gal
ft
W
$
Pump Sizing
Base Required GPH —
GPH After Fish Adj. —
Total Dynamic Head (ft) —
Buy Pump Rated At —
Tubing Diameter —
Operating Cost
Monthly Energy Cost —
How to Use This Calculator
- Enter your pond or fountain water volume in gallons.
- Select the turnover rate (1× pond, 2× filter, 3× waterfall).
- Enter head height — the vertical lift from water surface to discharge.
- The calculator shows required GPH, rated pump GPH, and recommended tubing size.
Formula
Required GPH = Volume (gal) × Turnover Rate (per hour)
Head Derate: ~10% output loss per 5 ft of head height. Buy pump rated at GPH / (1 − head_derate).
Example
Example: 500-gallon pond, 2× filter turnover, 4 ft head → Required GPH = 1,000. With 4 ft head (~8% loss) → buy pump rated at ~1,087 GPH. Use 1-inch tubing.
Frequently Asked Questions
- A rule of thumb is to circulate the entire pond volume once per hour for a basic pond, twice per hour if using a filter, and three times per hour for waterfalls or streams. Multiply volume by the turnover rate to get required GPH.
- Head height is the vertical distance the pump must lift water from the surface to the discharge point. Every 5 ft of head reduces pump output by roughly 10%. Always buy a pump rated for more GPH than you need at the actual head height.
- Use 3/4-inch tubing up to about 600 GPH, 1-inch tubing for 600–1,500 GPH, and 1-1/4 inch or larger for higher flows. Undersized tubing creates friction loss and reduces pump performance.
- Yes. Koi produce significantly more waste than goldfish or native fish. For koi ponds, turn over the volume 2–3 times per hour and size biological filtration accordingly.
- A 60-watt pump running 24/7 at $0.13/kWh costs about $5.60 per month. Use the Professional calculator to enter your pump wattage and local electricity rate.
Related Calculators
Sources & References (5) ▾
- Aquascape Pond Pump Sizing Guide — Aquascape Inc.
- Pondkeeper UK – How to Choose a Pond Pump — Pondkeeper
- Speichert G — Water Garden: A Guide to Small Freshwater Gardens — Storey Publishing
- Penn State Extension – Pond Management — Penn State Cooperative Extension
- USDA NRCS Ponds – Planning, Design & Construction (Agriculture Handbook 590) — USDA NRCS