Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Total pool gallons
15,268
Surface area
452
sq ft
Total cubic feet
2,036
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter diameter (ft).
- 2Enter water depth (ft).
- 3Read your total pool gallons on the right — it updates as you type.
- 4Hit Share to keep the scenario or send it to someone.
About this calculator
Round above-ground pools are one of the most common backyard pool styles, and their volume formula differs from a rectangular pool because it's based on a circle's area rather than a simple length-times-width rectangle. This calculator takes the pool's diameter and its water depth, computes the circular area using radius squared times pi, then multiplies by depth and the 7.5 gallons-per-cubic-foot constant to get total gallons. Round pools typically hold a single constant depth rather than sloping from shallow to deep, which actually makes this calculation simpler than a rectangular in-ground pool's average-depth math. Getting the gallon count right matters most when dosing shock or balancing chlorine after a fill, since manufacturer dosing instructions are almost always written per 10,000 gallons, and a round pool's actual capacity is easy to misjudge by eye given how much water a circular footprint holds compared to what it looks like from the deck.
Worked example
Using the values the calculator loads with:
Inputs
- Diameter: 24 ft
- Water depth: 4.5 ft
Results
- Total pool gallons: 15,268
- Surface area: 452
- Total cubic feet: 2,036
What each field means
Inputs
- Diameter (ft)
- The diameter used in the calculation, measured in ft. Starts at 24 ft so you have a working example on load. Accepted range: 5–60 ft.
- Water depth (ft)
- The water depth used in the calculation, measured in ft. Starts at 4.5 ft so you have a working example on load. Accepted range: 1–12 ft.
Results
- Total pool gallons
- Returned as a whole number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Surface area
- sq ft
- Total cubic feet
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How much water does a 24 ft round pool hold?
At a typical 4.5 ft depth, a 24 ft diameter round pool holds roughly 15,250 gallons, which is why most above-ground pool manufacturers list capacity directly on the box for common diameter and depth combinations.
Do above-ground round pools have varying depth?
Most standard above-ground round pools hold a single constant depth throughout, unlike in-ground pools that slope, which simplifies the math to one depth measurement instead of an average.
Why is pi used in this formula?
A round pool's surface is a circle, and a circle's area is calculated as pi times radius squared, so that constant is required to convert diameter into a usable area before multiplying by depth.
How do I measure water depth accurately?
Measure straight down from the water's surface to the pool floor at a few points if the liner isn't perfectly flat, and use the actual filled water line rather than the pool wall's full height.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Rectangular Pool Gallons Calculator
Convert a rectangular pool's dimensions into total gallons for chemical dosing.
Oval Pool Gallons Calculator
Convert an oval above-ground pool's length, width, and depth into total gallons.
Hot Tub Gallons Calculator
Estimate a hot tub or spa's total water volume for accurate chemical dosing.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Round Pool Gallons Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/pool-gallons-round-calculator
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/pool-gallons-round-calculator" target="_blank" rel="noopener">Round Pool Gallons Calculator — RevenueLab</a> (2026).</p>
Source: [Round Pool Gallons Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/pool-gallons-round-calculator) (2026).