How Many Gallons in a 30 Ft Round Pool?
Water in the pool
22,896 gallons
Round, 30 ft across, filled to a 52 in wall, which is 4.33 ft. Flat bottom, so the average depth is the wall height.
Filling this pool on a garden hose takes 2 days of continuous water. Most water utilities sell a bulk fill, and some will not meter a pool fill through the sewer charge if you call first, which is worth more than the hose.
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How that number is worked out
These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.
- Pool shapeRound
- Length or diameter30 ft
- Width30 ft
- Shallow end depth4.33 ft
- Deep end depth4.33 ft
- Fill rate8 gal/min
- Turnover target8 hours
Water in the pool22,896 gallons
Filling this pool on a garden hose takes 2 days of continuous water. Most water utilities sell a bulk fill, and some will not meter a pool fill through the sewer charge if you call first, which is worth more than the hose.
| Surface area | 706.9 sq ftpi r squared on the diameter |
|---|---|
| Average depth | 4.33 ftmidpoint of shallow and deep |
| Volume | 3,060.7 cu ft7.48 gallons in each |
| Water weight | 95.5 tons190,950 lb |
| Fill time | 47.7 hoursat 8 gallons a minute |
| Pump for turnover | 47.7 gal/minwhole volume once in 8 hours |
| Heater to raise 10 degrees | 1,909,000 BTU8.34 BTU per gallon per degree |
| Liquid chlorine for a 10 ppm shock | 1.83 gal12.5 percent, sold in gallon jugs, so buy 2 |
| Salt to reach 3,200 ppm | 612 lb16 bags at 40 lb, from zero |
The material list this produces
| Water, gallons | 22,896 |
|---|---|
| Liquid chlorine 12.5 percent, gal | 2 |
| Salt, 40 lb bags | 16 |
| Pump, gal/min | 48 |
Diameter compared
Same wall height as this page, at every diameter the round pool shelf comes in. Water goes up with the square of the diameter, so the jump from 24 to 27 feet costs more water than the jump from 8 to 15.
| Diameter | Water in the pool | Surface area | Fill time |
|---|---|---|---|
| 8 ft | 1,629 gallons | 50.3 sq ft | 3.4 hours |
| 12 ft | 3,664 gallons | 113.1 sq ft | 7.6 hours |
| 15 ft | 5,724 gallons | 176.7 sq ft | 11.9 hours |
| 18 ft | 8,243 gallons | 254.5 sq ft | 17.2 hours |
| 21 ft | 11,219 gallons | 346.4 sq ft | 23.4 hours |
| 24 ft | 14,654 gallons | 452.4 sq ft | 30.5 hours |
| 27 ft | 18,546 gallons | 572.6 sq ft | 38.6 hours |
| 30 ft | 22,896 gallons | 706.9 sq ft | 47.7 hours |
| 33 ft | 27,704 gallons | 855.3 sq ft | 57.7 hours |
What else matters here
22,896 gallons and 707 square feet of surface. Thirty feet is near the top of what is made as a round above ground pool, and at this size the running costs, not the purchase price, decide whether it was a good idea.
The surface area is what drives them. Evaporation, chemical burn off and heat loss all happen at the surface, and this pool has almost three times the surface of a 18 foot round. Every uncovered day costs roughly three times the water, three times the chlorine and three times the heat. A solar cover on a pool this size is not an accessory, it is the thing that makes the numbers work.
Two days of continuous water to fill it. That is the point where a bulk fill by tanker is usually both cheaper and faster than the hose once the sewer charge is counted, and it is worth asking the utility what they charge before the pool is even up.
What this calculator assumes
- A cubic foot of water is 7.48 gallons and a gallon weighs 8.34 pounds. Those two numbers do all the work on this page.
- Average depth is taken as the midpoint of the shallow and deep ends. That is exact for a pool with one straight slope between them and slightly generous for a pool with a flat shallow shelf and a hopper, which is the safer way for it to be wrong when you are buying chemicals.
- A round pool uses the diameter and ignores the width. An oval is figured as an ellipse, which is length times width times pi over four, not as a rectangle.
- Turnover is the time the pump takes to move the whole volume once. Eight hours is the common residential target and some health codes for public water are stricter, so check yours before you size a commercial pump off this.
- Liquid chlorine trade percent is defined so that one gallon of it raises ten thousand gallons of water by that many parts per million. One gallon of 12.5 percent raises 10,000 gallons by 12.5 ppm, which is where the dose row comes from rather than a chart.
- Salt is figured from zero to 3,200 ppm, which is the middle of the range most chlorine generators want. A pool that already has salt in it needs a test first, because salt only leaves with the water.
Questions people ask
Is that the number printed on the box?
It is the same basis. A manufacturer quotes the pool filled to the top of the wall, which is what this page computes. In the yard you fill to the middle of the skimmer mouth, roughly six inches down, so the water actually in it lands about ten percent under the printed figure. Both numbers are useful: buy the cover and the liner off the printed one, and dose chemicals off the real one.
What does it cost to heat a 30 foot round?
The calculator gives the energy rather than the price, because the price is local. Raising this pool ten degrees takes about 1.9 million BTU, which is the figure to take to a heater dealer or a propane supplier. What changes the answer most is not the heater, it is whether the pool is covered overnight, because an uncovered pool loses most of its heat off the surface while nobody is in it.
Why is the salt figure from zero?
Salt only leaves a pool with the water, through splash out, backwash and a leak. It does not evaporate. So the bag count here is what an empty pool needs to reach 3,200 ppm, and a pool that has run on salt before needs a test first or you will overshoot it. Adding salt is easy and taking it out means draining water.
The pool volume calculator takes any dimensions you like and hands back the same list.