ContractorHandbook

How Many Gallons in a 33 Ft Round Pool?

Water in the pool

27,704 gallons

Round, 33 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 2.4 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.

It does not stop at a number.

When the figures look right, the pool water and chemical list downloads as a real PDF with your business details on it, built inside your own browser. Nothing you type is uploaded anywhere.

average depthshallowdeeplength, ftsurface area x average depth x 7.48 = gallons
A pool with two depths is worked as one average depth, which is close enough for water and exactly how the chemical and turnover numbers are derived. Volume in cubic feet times 7.48 is gallons, and everything else on the page follows from that one figure.

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 diameter33 ft
  • Width33 ft
  • Shallow end depth4.33 ft
  • Deep end depth4.33 ft
  • Fill rate8 gal/min
  • Turnover target8 hours

Water in the pool27,704 gallons

Filling this pool on a garden hose takes 2.4 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 area855.3 sq ftpi r squared on the diameter
Average depth4.33 ftmidpoint of shallow and deep
Volume3,703.4 cu ft7.48 gallons in each
Water weight115.5 tons231,049 lb
Fill time57.7 hoursat 8 gallons a minute
Pump for turnover57.7 gal/minwhole volume once in 8 hours
Heater to raise 10 degrees2,310,000 BTU8.34 BTU per gallon per degree
Liquid chlorine for a 10 ppm shock2.22 gal12.5 percent, sold in gallon jugs, so buy 3
Salt to reach 3,200 ppm740 lb19 bags at 40 lb, from zero

The material list this produces

Water, gallons27,704
Liquid chlorine 12.5 percent, gal3
Salt, 40 lb bags19
Pump, gal/min58

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.

DiameterWater in the poolSurface areaFill time
8 ft1,629 gallons50.3 sq ft3.4 hours
12 ft3,664 gallons113.1 sq ft7.6 hours
15 ft5,724 gallons176.7 sq ft11.9 hours
18 ft8,243 gallons254.5 sq ft17.2 hours
21 ft11,219 gallons346.4 sq ft23.4 hours
24 ft14,654 gallons452.4 sq ft30.5 hours
27 ft18,546 gallons572.6 sq ft38.6 hours
30 ft22,896 gallons706.9 sq ft47.7 hours
33 ft27,704 gallons855.3 sq ft57.7 hours

What else matters here

27,704 gallons is the largest round above ground pool in ordinary production and it holds more water than a 20 by 40 inground with a three to six foot slope. 855 square feet of surface, 115 tons of water, and a 33 foot circle of yard that has to be flat to within an inch.

An eight hour turnover is 58 gallons a minute. That is 3,460 gallons an hour and it is beyond most single speed above ground pumps and most cartridge filters sold in the same aisle as the pool. At this volume the filter is sized like an inground filter, and a variable speed pump pays for itself because it is running long hours.

Fifty eight hours on a hose, so realistically it gets a tanker. The number worth carrying to that call is the volume itself: 27,704 gallons is about four tanker loads at the usual 6,000 to 7,000 gallon capacity, and knowing that before you ring means you are quoting them rather than the other way round.

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.

Is 33 feet too big for an above ground pool?

It is the largest round that is widely made, and nothing about the volume is a problem in itself. What gets people is the yard: a 33 foot circle needs roughly 35 feet of genuinely level ground with access all the way round it for the wall and the track, and a slope that has to be cut down more than about six inches at one side usually needs a retaining wall, which costs more than the pool.

Does the water weight matter?

It decides what the pool can stand on. A gallon of water weighs 8.34 pounds, so the load is real tonnage and it is spread over the footprint rather than carried on a beam. A round above ground pool wants level, compacted ground, not a deck and not a slope that has been shimmed flat on one side. The ground under it settles once, when you fill it.

Different numbers?

The pool volume calculator takes any dimensions you like and hands back the same list.

Other common sizes