How much water will your pond hold?
Choose a rectangular, circular or elliptical water surface and enter its actual average water depth. The calculator reports US gallons, liters and cubic meters, with known submerged displacement subtracted. Water capacity is separate from maximum excavation depth used for preliminary liner sizing.
How should shelves and slopes affect average depth?
Average depth must represent the whole water footprint, including shallow shelves and sloped sides. Do not use maximum depth as if every part were equally deep. For a complex pond, measure zones and combine their area-weighted depths, or use a measured fill volume. No arbitrary shape factor is applied.
Which volume formulas are used?
Rectangular surface area is length × width. A circle uses πd²/4, and an ellipse uses π × major axis × minor axis/4. Multiply by actual average depth, then subtract separately measured submerged displacement. Inside dimensions at the intended waterline are more useful than outside landscaping dimensions.
Water volume = surface area × actual average depth − known displacement; liner dimension = maximum span + 2 × maximum depth + 2 × edge allowance
SpanLiner pathDepth
What does a ten-by-eight-foot pond example hold?
A 10 × 8 ft rectangle at 2 ft actual average depth contains 160 ft³, about 1,196.883 US gallons or 4,530.695 liters before displacement. A 3 ft maximum excavation depth does not change that water estimate unless the actual average water depth changes.
How is the preliminary flat liner envelope calculated?
Each liner dimension is maximum span + twice maximum excavation depth + twice edge allowance. With 10 × 8 ft spans, 3 ft maximum depth and 1 ft allowance at every edge, the envelope is 18 × 16 ft. This is a preliminary estimate, not a substitute for measuring the actual excavation cross-section and manufacturer anchoring requirements.
Can an available liner sheet fit the envelope?
Enter both available sheet dimensions. The calculator checks either orientation against the estimated envelope. It does not design seams, waterfall channels or complex penetrations. Maximum depth must not be lower than average water depth; verify both against excavation and intended water level.
How do circulation and fill-flow calculations work?
Required circulation flow equals liters divided by the chosen period in hours. Conversely, actual delivered L/hour gives a nominal circulation period. Enter flow at the actual system head, not just a zero-head pump label. Fill time uses measured L/min and assumes it stays constant. Fish stocking, filtration and water treatment are separate design tasks.
Which input units and assumptions should you check?
Use the labeled units and measured project values. Optional fields remain blank unless their data are available; paired fields must be entered together. Average water depth must represent shelves and slopes. Liner envelope is a preliminary bound; verify the actual excavation path. Pump flow is at operating head, not a zero-head label rating.
| Input | Unit basis | When used |
|---|---|---|
| Maximum pond length | ft / m | shape:rectangle |
| Maximum pond width | ft / m | shape:rectangle |
| Ellipse major axis | ft / m | shape:ellipse |
| Ellipse minor axis | ft / m | shape:ellipse |
| Round pond diameter | ft / m | shape:circle |
| Actual average water depth | ft / m | all modes |
| Known submerged displacement (optional) | ft³ / L | all modes |
| Maximum excavated depth | ft / m | liner:yes |
| Liner allowance at each edge | ft / m | liner:yes |
| Available liner sheet length (optional) | ft / m | liner:yes |
| Available liner sheet width (optional) | ft / m | liner:yes |
| Chosen circulation period (hours, optional) | as labeled | all modes |
| Actual delivered flow at working head (L/hour, optional) | as labeled | all modes |
| Measured fill flow (L/min, optional) | as labeled | all modes |
| Water price per cubic meter (optional) | as labeled | all modes |
How can you compare and save different scenarios?
Calculate and save a baseline to comparison, change one input and calculate again. Review the itemized results before transferring values. Copy or share the result, download the input and result sheet, or print the worksheet. Clear changes removes the current inputs and results, and refresh starts clean.
Which related calculators help with the next step?
Use Pool Volume Calculator and Pipe Volume Calculator. Check that the measurement units and scope match before using a result as an input elsewhere.
