Pond Calculator — Volume, Liner, Pump & Turnover

Design smarter ponds with instant volume, surface area, and depth calculations included. Size liners automatically with overlaps and depth allowances for safety and durability. Estimate pump flow, filter capacity, and turnover for clear water year-round clarity. Toggle imperial or metric, preview graphs, and export results easily. Build confidently with precise, practical, pond-ready numbers today.

Inputs

ft
ft
ft
ft²
If irregular, provide top surface area.
ft
ft
Label Area % Depth
Average depth and maximum depth are computed from zones.
Avg — ft • Max — ft • Sum 0%
ft
Extra material past rim, each side.
hours
Common: koi ~1h; planted ~1.5–2h.
ft
in
ft
ft
Use additional length to approximate bends, valves, tees.
C
Typical: new PVC 150, older PVC 140, steel ~120.

Example Scenarios

Name Shape L / D W Avg d Max d Units

Results

US units
Surface area
ft²
Volume
gal
Liner size (W × L)
ft × ft
Estimated perimeter
ft
Recommended pump flow
gph
Based on target turnover time. Choose a pump meeting this at your head.
Static head
ft
Friction head
ft
Total dynamic head
ft
Graph: Flow vs turnover time for the calculated volume.
Graph: Estimated head (static + friction) vs turnover time.

Formulas Used

  • Rectangle surface area: A = L × W.
  • Circle surface area: A = π × (D/2)².
  • Oval surface area (ellipse): A = π × a × b where a=L/2, b=W/2.
  • Volume: V = A × average depth.
  • Weighted average depth (shelves): d̄ = Σ(pᵢ·dᵢ) with Σpᵢ = 1.
  • Unit conversions: 1 ft³ = 7.48052 gal, 1 m³ = 1000 L, 1 m = 3.28084 ft, 1 in = 25.4 mm.
  • Perimeter: rectangle P = 2(L+W); circle P = πD; oval (approx) P ≈ π[3(a+b)−√((3a+b)(a+3b))].
  • Liner size (rectangle): (L + 2·maxDepth + 2·overlap) × (W + 2·maxDepth + 2·overlap). Similar for circle/oval using diameter/axes.
  • Pump flow from turnover: Flow = Volume ÷ TurnoverTime.
  • Hazen–Williams friction head (US customary): hf = 10.67·L·Q1.852 / (C1.852·d4.871), Q in gpm, L in ft, d in inches. Head in feet.
  • Total dynamic head: TDH = static head + friction head.
Notes: This calculator estimates head at the turnover-selected flow. Select a pump whose curve delivers at least the recommended flow at your calculated TDH.

How to Use

  1. Select units and pond shape.
  2. Enter dimensions (or surface area for irregular shapes).
  3. Optional: enable shelf-depth modeling and enter zone percentages and depths.
  4. Provide liner overlap, turnover time, and optional head-loss parameters.
  5. Click Calculate to update results and the flow & head graphs.
  6. Export results to CSV or PDF for records or quotes.
  7. Load an example to quickly see different scenarios.

FAQs

Clear-water ponds with fish often target ~1 hour. Planted or lightly stocked ponds can use 1.5–2 hours. Faster turnover improves clarity but increases energy use and pump wear.

A common allowance is 1 ft (0.3 m) beyond the rim on each side to anchor under rock or edging. Increase for steep banks or soft soils.

It assumes the top surface area you enter and multiplies by average depth. Shelves or changing cross-sections reduce accuracy, so verify with fill meters if possible.

Yes. Take a depth-weighted average: add shallow shelves and deep zones proportionally. Maximum depth is the deepest zone and is used for liner sizing.

Pumps deliver less flow against elevation and friction losses. Choose a curve-rated pump whose flow at your total dynamic head meets or exceeds the recommended flow here.

Yes. Use the Units menu. All inputs and outputs update automatically, and the charts toggle their axis labels.

Enable the perimeter option. The calculator uses formulas per shape. For ovals, a Ramanujan approximation provides a close estimate for ordering edging materials.

Related Calculators

Pool Volume CalculatorTank Volume Calculator

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.