Find how many gallons a 30 ft round pool holds from its average water depth, in US gallons and litres, with a gallons chart for 12 to 33 ft round pools. Enter the values shown in the calculator to get a practical planning estimate.
Free interactive calculatorPool Volume
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FREE ONLINE CALCULATOR
30 ft Round Pool Gallons
Enter the inside water dimensions and average depth. The estimate updates when you calculate.
GAL
YOUR ESTIMATE
Estimated pool water volume
Planning estimate
Pool volume—US gallons
Metric volume—Litres
Cubic feet—Water volume
Cubic metres—Water volume
Measurement note: This is an estimate based on a regular geometric shape and average water depth. Steps, benches, sloped floors and freeform curves can change the actual capacity. Use inside waterline dimensions.
ABOUT THIS TOOL
What this calculator helps with
Pool Volume
A 30 ft round pool holds roughly 15,850 to 26,450 gallons, depending on how deep the water is. Its capacity is set by the inside diameter and the average water depth, so the 30 ft label on its own does not give an exact figure. Enter your average depth below for gallons and litres, or use the chart to compare 24, 27 and 30 ft round pools.
Why this calculation matters
A reliable gallon figure feeds water treatment, pump and filter sizing and heating estimates. Using the water depth rather than the wall height, and the inside diameter rather than the outside, makes the estimate more representative of what the pool really holds.
Details to have ready
Inside diameter measured across the waterline.
Average water depth, especially if the floor slopes.
Whether the pool has built-in steps, benches or other features.
Correct conversion between cubic feet and US gallons (7.48 gallons per cubic foot).
How to prepare
Confirm the pool is round and measure its inside diameter.
Measure the water depth at several points if the floor is not flat and average it.
Enter the diameter and depth, or check the chart for the closest match.
Record the gallons and use them in your chemical, pump and heating calculations.
Note: Pool capacity is approximate unless the actual inside dimensions and average water depth are known.
MEASUREMENT & CALCULATION GUIDE
How many gallons does a 30 ft round pool hold?
A 30 ft round pool gallons estimate is based on the pool's inside diameter and average water depth. The 30 ft label alone is not enough to know its exact capacity, because water depth, wall profile and the actual waterline dimensions vary between pools.
US gallons ≈ π × (diameter ÷ 2)² × average depth × 7.48052
At an illustrative average water depth of 4 ft, a 30 ft round pool holds about 21,140 US gallons before adjustments for steps, benches or floor slope. Use the editable diameter and enter the average water depth measured in your pool. This also answers common searches like “30 ft round pool how many gallons”, “how many gallons in 30 ft round pool” and “how many gallons is a 30 ft round pool”.
Gallons in a 24, 27 and 30 ft round pool
The chart compares round pools from 12 to 33 ft across common water depths, so you can read off a 24 ft, 27 ft or 30 ft figure at a glance. For a dedicated 24 ft calculation see the 24 ft pool gallons calculator. A 30 ft above ground pool is usually filled to about 4 ft, which is roughly 21,150 gallons or 80,000 litres.
Round pool gallons by diameter and average water depth (US gallons)
Diameter
3 ft
3.5 ft
4 ft
4.5 ft
5 ft
12 ft
2,550
2,950
3,400
3,800
4,250
15 ft
3,950
4,650
5,300
5,950
6,600
18 ft
5,700
6,650
7,600
8,550
9,500
21 ft
7,750
9,050
10,350
11,650
12,950
24 ft
10,150
11,850
13,550
15,250
16,900
27 ft
12,850
15,000
17,150
19,250
21,400
30 ft
15,850
18,500
21,150
23,800
26,450
33 ft
19,200
22,400
25,600
28,800
32,000
Figures are rounded to the nearest 50 gallons and use π × radius² × depth × 7.48052. Multiply by 3.785 for litres. Use the average water depth, not the wall height.
It depends on the water depth. A 30 ft round pool holds roughly 18,500 gallons at 3.5 ft, 21,150 gallons at 4 ft, 23,800 gallons at 4.5 ft and 26,450 gallons at 5 ft of average depth.
How many gallons in a 30 foot above ground pool?
Most 30 ft above ground pools have 48 to 54 inch walls but are filled below the top, so the average water depth is usually a little under the wall height. At a 4 ft water depth the pool holds about 21,150 gallons, or about 80,000 litres. Measure your real water depth for a better figure.
How many gallons in a 27 foot round pool?
A 27 ft round pool holds about 17,150 gallons at a 4 ft water depth, 19,250 gallons at 4.5 ft and 21,400 gallons at 5 ft. The chart on this page covers 12 to 33 ft round pools at several depths.
How many gallons in a 24 foot round pool?
About 13,550 gallons at 4 ft and 15,250 gallons at 4.5 ft. See the 24 ft pool gallons calculator for a dedicated depth chart.
How do I calculate 30 ft round pool gallons by hand?
Work out the surface area with π × 15 × 15, which is about 707 square feet, then multiply by the average depth and by 7.48. At a 4 ft average depth that gives 707 × 4 × 7.48, or about 21,150 gallons.
How many litres are in a 30 ft round pool?
Multiply gallons by 3.785. At a 4 ft average depth the pool holds about 21,150 gallons, which is roughly 80,000 litres. The calculator shows gallons and litres together.
Should I measure the outside diameter?
No. For a water-volume estimate, use the inside diameter at the waterline. Measuring the outside of the wall includes the wall thickness and gives a number that is a little too large.
Will a sloped bottom change the estimate?
Yes. If the floor slopes, use the average depth rather than the deepest point. Add the shallow and deep readings together and divide by two for an even slope.
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