Know the water, not just the shape.

Pool Volume Calculator

Estimate pool water in US gallons, liters and cubic meters. Distinguish ellipses from capsule pools, account for depth changes and deduct known solid displacement.

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Your measurements

1Shape & dimensions

Dimension unit

Pool shape

Overall water length (ft)

Water width (ft)

Water diameter (ft)

How does the floor change?

Water depth (ft)For feet, 3 ft 6 in = 3.5 ft.

Shallow water depth (ft)

Deep water depth (ft)

Zones share the width above. Enter each non-overlapping length and its start/end water depths. Lengths are added; use equal start/end depths for a flat zone.

Depth zone 1

Zone length (ft)

Start depth (ft)

End depth (ft)

Depth zone 2

Zone length (ft)

Start depth (ft)

End depth (ft)

Depth zone 3

Zone length (ft)

Start depth (ft)

End depth (ft)

2Optional solid displacement

Submerged solid volume

Displacement unit

Deduct known steps or benches only if they are included in the geometric volume above. Do not deduct empty space above the waterline.

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A better measurement of your water

View the formulas ↗

Measure at the waterline

Use the inside water dimensions and water depth. Wall height and outside dimensions overstate the water volume.

Describe the floor

Use a flat depth, a genuinely uniform slope, or separate rectangular zones for changing floor sections.

Keep units explicit

Read US gallons, Imperial gallons, liters and cubic meters separately. Deduct measured submerged solids only once.

Open the printable measurement worksheet ↗

Small details. Better estimates.

Explore all 6 guides ↗

Guide 01 / Worked examples

Measure the water dimensions before calculating pool gallons

Use inside dimensions and actual water depth, with an example showing why wall height can overstate pool volume.

Read the guide ↗Guide 02 / Worked examples

Rectangular pools: when average depth works and when to use zones

Calculate a uniformly sloped rectangle, then compare it with a segmented floor where a simple endpoint average overstates water.

Read the guide ↗Guide 03 / Worked examples

Round, elliptical and capsule-shaped pools are different

Choose the correct curved pool outline and compare worked ellipse and semicircular-end volume estimates.

Read the guide ↗Guide 04 / Worked examples

Pool volume units: US gallons, Imperial gallons, liters and cubic meters

Convert pool capacity consistently and see why an unlabeled gallon value can cause a large mismatch.

Read the guide ↗Guide 05 / Worked examples

Account for pool steps, benches and tanning ledges once

Use either shallow-water zones or known solid displacement to account for ledges without subtracting the same space twice.

Read the guide ↗Guide 06 / Worked examples

How accurate is a pool volume estimate?

Understand measurement sensitivity, compare low and high scenarios, and improve the inputs that matter most.

Read the guide ↗

Common questions

Before you calculate

Is an oval always an ellipse?

No. A capsule pool has a straight central section with semicircular ends. An ellipse is curved throughout. The same outside dimensions give different areas.

Can I average shallow and deep depth?

Only when the floor changes uniformly across the relevant area. A long shallow platform and short deep section need separate zones, not a simple two-depth average.

Do I measure wall height or water depth?

Water depth at the current waterline. Empty space above the water is not part of the water volume.

Can I use the result to dose chemicals?

This is a geometric estimate, not a dosing instruction. Follow the product label, measured water chemistry and professional guidance for treatment decisions.