Free tool
Pool Volume Calculator
Enter your pool shape and dimensions and get the volume in gallons — plus surface area, cubic feet, and a shock-dose ballpark. The gallon count every chemical dose is based on. Free, no signup.
Pool volume
0 gal
- Surface area0 ft²
- Average depth0 ft
- Volume (cubic feet)0 ft³
- Volume (gallons)0 gal
- In liters0 L
- Shock estimate—
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Or download it now (PDF)How to calculate pool volume
Pool volume is the number every chemical dose, heater sizing, and turnover calculation is built on, and it comes down to three steps: surface area, average depth, and a conversion to gallons. The step people get wrong is depth — use the average, not the deep end.
1. Find the surface area
For a rectangle, area is length × width. For a round pool it is π × radius². An oval is about 89% of the rectangle that would bound it. The calculator applies the right formula when you pick the shape.
2. Use the average depth
If the pool slopes from a shallow end to a deep end, add the two depths and divide by two. A pool that runs 3 ft to 8 ft averages 5.5 ft, not 8 — using the deep end alone would overstate the volume by nearly half and throw off every dose.
3. Convert to gallons
Multiply surface area by average depth for cubic feet, then multiply cubic feet by 7.48 to get gallons. That single number sets your chlorine, shock, algaecide, and pH doses — all of which are written per volume of water.
4. Dose from the label, not from memory
A rough shock treatment runs about a pound of cal-hypo per 10,000 gallons, but always read the product and test your water first. Current chlorine, cyanuric acid, and pH all change the right amount — the gallon count tells you the scale, the test tells you the dose.
Sizing the job is step one. Turning it into a priced, professional quote is faster inside CrewRivet. See the job pricing calculator, the HVAC BTU calculator, or the concrete calculator.
Pool volume calculator FAQ
- How do I calculate the volume of my pool in gallons?
- Find the surface area, multiply by the average depth to get cubic feet, then multiply cubic feet by 7.48 to get gallons. For a rectangle the area is length × width; for a round pool it is π × radius²; an oval is about 0.89 of its bounding rectangle. This calculator does all three for you.
- What is the average depth of a pool?
- If your pool has a shallow end and a deep end, the average depth is simply the two added together and divided by two — a pool that runs 3 ft to 8 ft averages 5.5 ft. Use that average, not the deep end, or you will badly overestimate the volume and over-dose chemicals.
- Why does pool volume matter for chemicals?
- Every chlorine, shock, algaecide, and pH adjustment dose is written per volume of water — usually per 10,000 gallons. Get the gallons wrong and every dose is wrong: too little does nothing, too much wastes product and can damage surfaces or irritate swimmers. The gallon count is the foundation of the whole chemistry.
- How much shock do I need for my pool?
- A common starting point is about one pound of cal-hypo shock per 10,000 gallons for a routine treatment, more for algae or after heavy use. Treat that as a ballpark — always read the product label and test your water first, since the right dose depends on your current chlorine, cyanuric acid, and pH levels.
- Is this pool calculator free?
- Yes — the live estimate is free with no email required. Enter your email only if you want the free Job Pricing Kit (pricing worksheet, markup cheat-sheet, and invoice + quote templates) sent to your inbox.