Calculator Pool
Last updated: June 2026 · Free · No sign-up required
Enter values above and click Calculate to see your result instantly.
How the Calculator Pool works
Behind the inputs above sits one rule: Gallons = length × width × average depth (ft) × 7.48. The tool evaluates it instantly with the values you enter.
For context, the sections beneath the calculator include typical values, a worked example you can recompute by hand, and an FAQ covering the practical details of pool volume calculator.
Quick reference
| Pool type | Volume formula (ft) | × gallons |
|---|---|---|
| Rectangular | L × W × avg depth | × 7.48 |
| Round | π × r² × avg depth | × 7.48 |
| Oval | π × (L/2) × (W/2) × depth | × 7.48 |
functions Shows the working, not just the answer
For students and teachers, the final number is only half the value. Every math tool here exposes the formula it applied, the intermediate steps, and the rounding rule, so you can follow along, check your homework, or use the answer in a proof or report with confidence.
calculate Accurate to the spec
Calculations use 64-bit floating point with sensible rounding for the domain (currency to 2 decimals, percentages to 4 decimals, algebra to 6 significant figures). Where exact rational arithmetic matters — fractions, factorials, simplification — we use a dedicated BigNumber path so 1/3 + 1/6 returns ½, not 0.49999.
school Free for classroom use
Educators are welcome to link to any math calculator on CalcaTools from a class site, Google Classroom, or worksheet. The pages are mobile-friendly, free, ad-supported (so we can keep them free) and have no sign-up wall — students just click and use them in class or at home.
tips_and_updates Pair with the spoke articles
Below the calculator we link a small set of plain-English explainer pages — "What is a percentage?", "Why does PEMDAS matter?", and so on. They cover the underlying concept in 4–6 short paragraphs. Read those before the calculator if the topic is new, or after if you want the extra context.
Interpretation guide
| Avg depth tip | Use |
|---|---|
| Constant depth | That single depth |
| Shallow + deep end | (shallow + deep) / 2 |
| Metric pools | Volume in m³ × 1000 = litres |
Formula & methodology
Formula: Gallons = length × width × average depth (ft) × 7.48
Pool volume is the water capacity. Find the volume in cubic feet, then convert to gallons (1 ft³ = 7.48 US gallons).
- Measure length, width and average depth in feet.
- For a sloped floor, average depth = (shallow + deep) / 2.
- Multiply length × width × average depth for cubic feet.
- Multiply cubic feet by 7.48 for US gallons.
Worked example: A 32 × 16 ft pool averaging 5 ft deep holds 32 × 16 × 5 × 7.48 = 19,149 gallons.