How Many Litres Is My Pool? Calculate Volume for Any Pool Shape

Knowing how many litres your pool holds is one of those numbers every pool owner needs at some point, but few actually have. It is the first thing a pool supplier asks when you are ordering chemicals. It determines whether your heater is sized correctly and your filtration system can keep up. And if you are measuring up for a new cover, understanding your pool's total water volume tells you exactly how much work that cover needs to do.

The problem is that the answer isn't on any label. Even pools built to the same dimensions by the same builder hold different volumes once you account for depth variations, irregular shapes, and internal features like steps and benches.

This guide gives you the formula for every common pool shape, ready-to-use reference tables so you can look up your volume in seconds, and a clear explanation of how that number affects every major pool decision you will make - from chemical dosing to cover selection.

Why Knowing Your Pool Volume in Litres Matters

Pool volume is not just a number. It is the foundation of almost every practical decision you make as a pool owner. Get it wrong by a significant margin, and you will chase water quality issues that appear to have no cause.

Getting Chemical Dosing Right

Every pool chemical product - chlorine, pH adjusters, algaecides, clarifiers, and phosphate removers - is dosed based on water volume. The standard dosing rate is calculated per 10,000 litres. If your pool actually holds 55,000 litres but you are dosing for 40,000, you are consistently under-dosing by 27%. Follow the product instructions correctly, and the result still looks like a water quality problem, when the issue is simply the wrong starting number.

Over-dosing carries the opposite risk: higher chemical costs, faster deterioration of pool covers and equipment, and water that irritates swimmers' skin and eyes. Our guide to the importance of water chemistry explains how to maintain the right balance once you have your volume confirmed.

Sizing Your Pool Equipment Correctly

Pumps, filters, and heaters are all rated by pool volume. A filtration system sized for a 40,000-litre pool running on a 70,000-litre pool will not turn over the water frequently enough — leaving chemical distribution uneven and increasing the load on chlorine to compensate. When you buy, upgrade, or audit equipment, your pool's actual volume is the number that determines whether the specification matches your pool's real needs.

Choosing the Right Pool Cover for Your Pool

This is where volume and surface area work together. Your cover is sized to the pool's surface area - length × width. But volume tells you how much work that cover needs to do. A larger-volume pool holds more heat and loses more water to evaporation each night, which means the performance difference between an entry-level solar blanket and a high-quality insulated cover compounds significantly over time. Read why do I need a pool cover? for a breakdown of exactly how much a well-matched cover saves.

How to Calculate the Volume of a Rectangular Pool

Rectangular pools are the most common shape in Australian backyards and the most straightforward to calculate. The formula is:

A pool that is 8 metres long, 4 metres wide, and 1.5 metres deep on average holds:

8 × 4 × 1.5 × 1,000 = 48,000 litres

All measurements must be in metres before you multiply. If you measure in centimetres, divide each figure by 100 first.

How to Find Your Average Depth

Most pools slope from a shallow end to a deeper section. To find your average depth:

1. Measure the depth at the shallowest point
2. Measure the depth at the deepest point
3. Add the two measurements and divide by two

For a pool with a 1.0m shallow end and a 2.0m deep end: (1.0 + 2.0) ÷ 2 = 1.5m average depth

For pools with a completely flat bottom, one measurement in the middle is sufficient. If your pool has a more complex profile, a shallow bench at both ends with a deep centre, take three or four depth measurements at regular intervals and average all of them.

Rectangular Pool Volume Reference Table

Find your pool size in the first column, then read across to your average depth. All volumes are in litres.

How to Calculate the Volume of a Round Pool

Round pools use the same principle as rectangular pools, but account for the circular surface area. The most practical formula is:

The 0.785 factor converts the square of the diameter to the actual circular area (it is a shorthand for pi divided by 4). For a round pool with a 5-metre diameter and 1.5-metre average depth:

5 × 5 × 0.785 × 1.5 × 1,000 = 29,438 litres

Round Pool Volume Reference Table

How to Calculate the Volume of an Oval Pool

Oval pools use the same 0.785 correction factor, applied across both the length and width dimensions:

For an oval pool that is 8 metres long, 4 metres wide, and 1.5 metres average depth:

8 × 4 × 0.785 × 1.5 × 1,000 = 37,680 litres

Oval Pool Volume Reference Table

How to Calculate the Volume of a Kidney or Freeform Pool

Freeform, kidney-shaped, and irregular pools do not fit a single formula. The most reliable method is to divide the pool into two or more simple sections, calculate the volume of each section separately, and add the results together.

For a kidney-shaped pool, a widely used practical approximation is:

For a kidney pool 9 metres long, with a widest width of 5 metres and a narrowest width of 3 metres, at 1.5 metres average depth:

(5 + 3) × 0.45 × 9 × 1.5 × 1,000 = 48,600 litres

This is an approximation, the actual volume depends on your pool's exact curvature. For a standard kidney shape it is accurate to within around 5%, which is close enough for chemical dosing purposes. For equipment sizing or commercial applications, a professional measurement is the more appropriate approach.

When to Get a Professional Measurement

If your pool has an irregular shape, significant internal steps or benches that reduce the water volume, or you are sizing commercial-grade equipment, professional measurement removes the guesswork entirely. Our detailed guide to how to measure your pool walks through the full measurement process, including complex and freeform shapes.

What Your Pool Volume Tells You About Cover Selection

Most people approach pool cover selection through the lens of budget and surface area. Volume is the lens that tells you what a cover is genuinely worth.

A pool holding 80,000 litres loses significantly more heat overnight than one holding 30,000 litres, even if both have a similar surface area. That larger thermal mass is working against you every night the pool is uncovered. The performance difference between a 400-micron entry-level solar blanket and a 610-micron high-insulation cover is proportionally far more valuable on a 70,000-litre pool — because there is so much more heat to retain.

For pools with a gas or electric heater, solar pool covers and thermal pool covers become more financially compelling as pool volume increases. More water to heat means more heat lost overnight if the cover is not performing at a high standard.

A good cover, deployed consistently with a quality pool cover roller, is what delivers the savings. A cover that is awkward to put on does not get put on consistently, and inconsistent use eliminates most of the water and energy savings the cover is designed to deliver. Factoring a roller into your budget from the start is not optional: it is the mechanism that makes the cover worth having.

A Smart Water Mark certified cover is independently verified to meet specific evaporation reduction standards - useful when comparing products where manufacturer claims are difficult to verify independently. For a full guide to matching your pool's measurements to the right cover, read how to buy and fit a pool cover and roller.

Why Elite Pool Covers Is the Right Partner for Your Pool

Once you know how many litres your pool holds, you have the information to make an informed cover decision. Getting the right cover matched to those exact measurements is where manufacturing experience and local expertise make a material difference.

Elite Pool Covers has been manufacturing pool covers in Perth, Western Australia, since 1989. Elite was the first Australian company to design, develop, and manufacture an automatic pool cover - a milestone in Australian pool industry history that established a track record of innovation sustained ever since. Elite was also the first to manufacture all-aluminium commercial rollers, produce high-insulation solar blankets, and design an in-ground hideaway roller system. Elite products are now exported to New Zealand, South Africa, Spain, France, and the United Arab Emirates.

When your pool requires a custom-cut cover because it is not a standard rectangle or the dimensions fall between standard sizes, having access to a manufacturer who makes covers here in Australia to exact specifications matters. There are no supply chain delays, no warranty claims that disappear offshore, and no disconnect between the measurement and what arrives.

From automated pool covers with concealed inground roller systems to high-performance solar and thermal blankets across every micron grade, Elite covers every pool type: residential and commercial. All products are manufactured to perform in Australian UV and chemical conditions, backed by pro-rata warranties from the manufacturer who built them.

Elite is a member of SPASA Australia, the peak industry body for the pool and spa industry in Australia, a standing built on over three decades of consistent performance.

Explore the full range of pool covers at poolcovers.com.au, or call the team directly on (08) 9516 1669 to discuss cover options for your pool's specific dimensions and requirements.

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