{"id":"pool-volume-calculator","name":"Pool Volume Calculator — Gallons by Dimensions","shortName":"Pool Volume Calculator","canonicalUrl":"https://calcurhome.com/calculators/pool-volume-calculator","catalogUrl":"https://calcurhome.com/api/calculators","category":{"id":"pools-spas","name":"Pools & spas","url":"https://calcurhome.com/calculators/category/pools-spas"},"language":"en-US","audience":"US homeowners, DIYers and home-project planners","primaryKeyword":"pool volume calculator","secondaryKeywords":["pool gallon calculator","swimming pool water calculator","calculate pool gallons","pool capacity calculator","round pool gallons calculator"],"description":"Estimate pool gallons and liters from length, width, shallow and deep depths, plus a shape factor for rectangular, oval, or round pools.","directAnswer":"Pool gallons equal surface footprint times average water depth times 7.48052 gallons per cubic foot. Use a 100% shape factor for rectangles and 78.54% for ellipses or circles measured across their widest axes. Slopes, benches, steps, and freeboard make dimensional results approximate, so compare against fill-meter or equipment records.","inputs":[{"key":"length","label":"Waterline length","unit":"ft","defaultValue":32,"min":0.1,"step":0.1},{"key":"width","label":"Waterline width","unit":"ft","defaultValue":16,"min":0.1,"step":0.1},{"key":"shallowDepth","label":"Shallow water depth","unit":"ft","defaultValue":3.5,"min":0.1,"step":0.1},{"key":"deepDepth","label":"Deep water depth","unit":"ft","defaultValue":8,"min":0.1,"step":0.1},{"key":"shapeFactor","label":"Footprint shape factor","unit":"%","defaultValue":100,"min":1,"max":100,"step":0.01,"help":"Use 100% for a rectangle or 78.54% for a true oval/circle measured by its bounding length and width."}],"formula":{"title":"Pool gallons formula","expression":"Gallons = length × width × shape factor × [(shallow depth + deep depth) ÷ 2] × 7.48052.","explanation":"Length and width create a bounding rectangle at the waterline. The shape factor retains all of a rectangle or π ÷ 4 of a true ellipse or circle. Multiplying adjusted surface area by average depth gives cubic feet, which are converted to U.S. gallons."},"measurementGuide":["Measure length and width across the water surface, not the outside of coping, walls, or decking.","Measure vertical water depth rather than wall height, and keep shallow and deep readings in feet.","Use 100% for rectangular footprints and 78.54% for true ellipses or circles measured across their bounding axes.","Divide freeform pools into simpler shapes or compare the result with plans and fill records instead of guessing one shape factor."],"buyingTips":["Use verified gallons when sizing pumps, filters, heaters, covers, treatment equipment, or chemical additions.","Compare equipment flow and capacity against manufacturer instructions, plumbing limits, and applicable local requirements.","Keep a permanent record of the best verified volume so future water-care calculations use the same baseline.","Treat steps, benches, spas, surge tanks, and water held below the operating waterline as separate adjustments when material."],"workedExample":{"title":"Rectangular backyard pool","scenario":"A rectangular pool measures 32 ft by 16 ft at the waterline, with depths of 3.5 ft and 8 ft and a 100% shape factor.","result":"Average depth is 5.75 ft and geometric volume is 2,944 ft³, producing an estimate of 22,023 US gallons, or approximately 83,365 liters."},"commonQuestions":[{"question":"How do I calculate gallons in a rectangular pool?","answer":"Multiply waterline length by waterline width and average water depth, then multiply cubic feet by 7.48052. Average depth is shallow depth plus deep depth divided by two when the bottom transitions reasonably evenly between them."},{"question":"What shape factor should I use for a round or oval pool?","answer":"Use 78.54% for a true circle or ellipse when length and width are full waterline diameters. That factor is π divided by four. Use 100% for rectangles, and divide freeform pools into measurable shapes for better accuracy."},{"question":"How do I find average pool depth?","answer":"For a pool with a reasonably uniform slope, add the measured shallow and deep water depths and divide by two. Benches, shelves, multiple breaks, diving wells, or large flat zones require section-by-section volumes for a better estimate."},{"question":"Why can actual pool gallons differ from this estimate?","answer":"Rounded walls, coves, steps, benches, freeboard, variable slopes, measurement error, and connected plumbing all affect actual water volume. Construction drawings, a calibrated fill meter, documented truck delivery, or reliable equipment records can provide a stronger baseline."}],"sources":[{"name":"Pentair — Pool Volume Calculator","url":"https://www.pentair.com/en-us/pool-spa/education-support/homeowner-support/calculators/pool-volume-calculator.html","note":"Pool-equipment manufacturer reference for estimating water volume from dimensions and average depth."},{"name":"National Institute of Standards and Technology — Volume Conversion Factors","url":"https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b9","note":"Federal reference for U.S. gallons, liters, cubic feet, cubic yards, and mass-density unit conversions."}],"defaultCalculation":{"inputs":{"length":32,"width":16,"shallowDepth":3.5,"deepDepth":8,"shapeFactor":100},"result":{"value":"22,023","unit":"US gallons","label":"Estimated pool volume","lines":[{"label":"Adjusted water surface","value":"512 sq ft"},{"label":"Average water depth","value":"5.75 ft"},{"label":"Water volume","value":"2,944 ft³"},{"label":"Metric volume","value":"83,365 L"}],"summary":"The entered dimensions represent approximately 22,023 US gallons, or 83,365 liters.","note":"Dimensional capacity is approximate. Verify usable volume from construction plans, a fill meter, known water delivery, or equipment records before chemical dosing or equipment sizing."}},"reviewedOn":"2026-07-24","disclaimer":"Planning estimate only. Verify product coverage, supplier rounding, local codes and structural requirements before purchase or construction."}