Calculate how much a pool weighs full of water from its length, width and depth, or from its gallons, with the result in pounds, kilograms or tons.

Estimate volume from the water-surface shape and a representative mean depth.

Leave blank if the depth is the same throughout. Volume uses the average of the two depths.

997 kg/m³ is fresh water near 25°C. Salt-chlorinated pools are close to fresh water; 1,025 kg/m³ is seawater.

Optional settings
Blank omits fill time. Enter a positive, constant flow for the empty-to-full estimate.

Pool Water Weight Formula

The following example problem outlines the steps and information needed to estimate the weight of the water in a pool. The calculator uses density × volume. Its default 997 kg/m³ approximates fresh water near 25°C; use a density appropriate to the actual temperature and dissolved salts. Water mass alone does not establish structural capacity.

m = ρ V

Variables:

  • m is water mass in kg, and ρ is the selected density in kg/m³
  • V is water volume in m³; one US gallon is 0.003785411784 m³

Convert volume to m³ and multiply by the selected density to find mass in kg. Divide kilograms by 0.45359237 for pounds, or by 1,000 for metric tonnes.

How to Calculate Pool Water Weight?

The following steps outline how to calculate the pool water weight.

  1. First, determine the total volume of water in the pool (US gallons).
  2. Next, convert US gallons to m³ and use m = ρV with the selected density.
  3. Finally, calculate the water weight.
  4. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

total volume of the pool (gallons) = 500

At the default density, m = 500 × 0.003785411784 × 997 ≈ 1,887.03 kg ≈ 4,160.18 lb.