Swimming Pool Volume Calculator
Calculate the total water volume of any rectangular swimming pool using its length, width, and average depth. Ideal for sizing pumps, planning chemical treatments, and estimating fill costs.
About this calculator
The volume of a rectangular swimming pool is found with the simple geometric formula: volume = length × width × depth, where all measurements are in meters and the result is in cubic meters (m³). One cubic meter equals 1,000 liters, so multiply m³ by 1,000 to get liters — a handy conversion for chemical dosing. For pools with a sloped floor, use the average depth: (shallow end depth + deep end depth) / 2. Accurate volume is the foundation of every pool maintenance calculation — the right amount of chlorine, pH adjuster, algaecide, or salt all depend on knowing how many liters of water you're treating. Errors in volume estimation directly cause under- or over-dosing of chemicals.
How to use
Example: a backyard pool that is 10 m long, 4 m wide, and has a shallow end of 1.2 m and a deep end of 2.0 m. Step 1 — average depth: (1.2 + 2.0) / 2 = 1.6 m. Step 2 — apply formula: 10 × 4 × 1.6 = 64 m³. Step 3 — convert to liters: 64 × 1,000 = 64,000 liters. This 64,000 L figure is what you'll use for all chemical dosage calculations and when sizing your filtration pump's turnover rate.
Frequently asked questions
How do I calculate the volume of a pool with a sloped or variable depth?
For a pool with a uniformly sloping floor, simply average the shallow and deep end depths: average depth = (shallow depth + deep end depth) / 2, then multiply by length × width. For more complex shapes with multiple slope changes, divide the pool into rectangular sections, calculate each section's volume separately, and sum them. Most residential pools can be accurately estimated with the single average-depth method, typically within 2–3% of true volume.
How many liters of water does a standard Olympic swimming pool hold?
An Olympic pool is 50 m long, 25 m wide, and 2 m deep. Using volume = 50 × 25 × 2 = 2,500 m³, which equals 2,500,000 liters (2.5 million liters). That's enough to fill about 10,000 standard bathtubs. Knowing this benchmark helps you contextualize your own pool's volume — a typical 8 m × 4 m backyard pool at 1.5 m average depth holds around 48,000 liters, or about 2% of an Olympic pool.
Why does accurate pool volume matter for chemical dosing?
Chemical dosages are always specified per unit volume — for example, 'add X grams of chlorine per 10,000 liters.' If your volume estimate is off by 20%, you'll consistently over- or under-dose. Too little chlorine allows algae and bacteria to grow, risking illness. Too much chlorine irritates eyes and skin, damages pool surfaces, and wastes money. Accurate volume is also essential when calculating cyanuric acid stabilizer levels, salt for saltwater systems, and pH adjustment chemicals.