How Many Gallons in a 9 ft Round Pool?
Bestway lists its Steel Pro 9 ft × 26 in round metal-frame pool at 851 gallons. Pools labeled "9 ft" are mostly this kind of short frame pool, and the water they hold depends on the wall height and the fill line.
Always follow your product’s label directions. Pool and spa chlorine, bromine, shock and algaecides are EPA-registered pesticides: use products labeled for pool or spa use, and don’t swim or soak until levels are within the limit on your product’s label. If this page and a label disagree, the label wins.
On this page (8 sections)
A 9 ft round pool sits between the small inflatable rings (8 ft) and the 10 ft pools that families buy for a patio. There are fewer 9 ft models than either neighbor, so this page is mostly about not mixing it up with a pool of a similar name.
Quick answer: 9 ft round pool gallons by wall height
Find your wall height (20, 26, 30 or 36 inches are the usual ones) in the data block. It shows volume at full fill and at the usual fill line for frame and inflatable pools, in gallons and liters, plus starting doses for that volume.
| Wall height | Geometry | Frame pool estimate (× 0.93) | Inflatable estimate (× 0.87) |
|---|---|---|---|
| 42 in wall | 1,499 gal5,675 L | 1,394 gal | 1,304 gal |
| 48 in wall | 1,713 gal6,485 L | 1,593 gal | 1,490 gal |
| 52 in wall | 1,856 gal7,026 L | 1,726 gal | 1,615 gal |
| 54 in wall | 1,927 gal7,296 L | 1,792 gal | 1,677 gal |
Geometry = π/4 × diameter² × water depth × 7.48. Real pools hold less than the nominal size suggests. The factors are medians of 26 manufacturer capacities (our own calculation).
| Change | Amount |
|---|---|
| +1 ppm FC (12.5% liquid chlorine) | 1.6 fl oz48 mL |
| +10 ppm TA (baking soda) | 3.6 oz101 g |
| +10 ppm CYA (stabilizer) | 2.1 oz60 g |
Closest full chart: 2,000 gal dose chart.
Which 9 ft pool do you have?
We found one 9 ft round model with a capacity on the maker's own site, and a few look-alikes that cause confusion.
| Pool | Shape and wall | What we know |
|---|---|---|
| Bestway Steel Pro 9 ft × 26 in | Round, metal frame, 26 in wall | 851 gallons (3,221 L) on Bestway's page |
| Bestway Steel Pro 9 ft 10 in × 6 ft 7 in × 26 in | Rectangle, 26 in wall | Different shape and size. Use a rectangle calculator, not this page. |
| Intex 9 ft round | None found | Intex's round pools in our database start at 6 ft and 8 ft, then jump to 10 ft. We could not confirm an Intex 9 ft model. |
One retail listing for a Bestway 9 ft × 26 in pool shows 1,056 gallons, which does not match Bestway's 851. We could not tell which number belongs to which version, so we use the manufacturer's page. If your manual prints a different number, use the manual.
Why 9 ft is easy to mismeasure
- Meters and feet. A pool sold as "2.74 m" is about 9 ft across, and one sold as "3 m" is closer to 9 ft 10 in. The extra 10 inches of width adds more water than it seems, because volume grows with the square of the diameter.
- Round and rectangle with the same name. Listings that say "9.8 ft" or "9 ft 10 in" are often rectangles. They share the 26 in wall and the look of the 9 ft round, but the water volume is not the same.
- Top ring or inside wall. Measure the diameter on the inside of the liner at floor level if you can. A frame pool's outer width, with the legs, is larger than the water.
Calculator: your exact depth
Enter 9 ft and the depth of water you actually keep. With a metal frame, many people run the water an inch or two below the top. Use that lower number.
Dosing a pool this size
With under 1,000 gallons, one level teaspoon more or less shifts your chlorine and pH readings in a way you can see on a test strip. The closest full chart is the 1,000 gallon dose sheet. For an 851 gallon pool, take the chart numbers and scale them down by about 15%. Do the arithmetic once, write it on the container, and stick to it.
The values in the data block above are your starting doses. After you add something, wait at least 30 minutes with the pump or water moving, then test. Ask the same question every time: how many parts per million (ppm) did that dose move the reading, in this pool? Your own pool will tell you more than any chart. If a dose moves free chlorine (FC) by less than expected, look for the cause, such as sun, heat, or lots of swimmers. See chlorine not holding.
Metal-frame pool sets usually include a small cartridge pump. A small pump moves water slowly, so run it long enough each day that every part of the pool sees the filter. If you are not sure what time to set, the pool pump run time calculator gives a starting estimate to adjust against your own tests.
Keep the water or change it?
A 9 ft pool holds under a thousand gallons, so a refill costs little. For a pool that sits for weeks between uses, a cover and weekly tests help keep the water clear. If the water turns green, the green pool page walks through the fix. For light use in hot weather, a fresh fill instead of treatment can be the simpler plan. Check the cost with the pool fill cost calculator.
Another small size to compare is the 8 ft round pool, and one step up is the 10 ft round pool. See also the above ground pool gallons chart for every common size on one page.
Safety. Measure each product separately in a clean, dry, labeled container. Never mix chlorine with acid or with another chlorine product, and keep chemicals away from children and pets. Poison Control: 1-800-222-1222. Always follow the product label. It is a violation of federal law to use a pesticide product in a manner inconsistent with its labeling.
FAQ
How many gallons is a 9 ft round pool?
Bestway lists its Steel Pro 9 ft × 26 in round pool at 851 gallons. Other wall heights hold more or less. Use the table above for your height.
How much chlorine does a 9 ft pool need?
The dose depends on the product and its strength, so use the 1,000 gallon dose sheet and scale it to your volume, then test. Follow the product label.
How many chlorine tablets for a 9 ft pool?
Most 3 in tablets are meant for larger pools, so a whole tablet is usually too much. Use the tablets calculator for a partial tablet and test before adding another.
Is a 9 ft pool the same as 2.74 m?
Almost. 2.74 m is about 9 ft. A 3 m pool is closer to 9 ft 10 in, which holds noticeably more water.
Sources
- Bestway Steel Pro 9 ft × 26 in round (851 gallons), read 2026-10-06 via search result: bestwayusa.com
- Volume formulas, correction factors, and dose math: methodology