Pool Evaporation Calculator
Estimate how much water your pool loses to evaporation and how much a pool cover can save.
Pool Cover Savings (vs. no cover)
How Pool Evaporation Is Calculated
Pool evaporation depends on the difference between the water surface temperature and the air's moisture-holding capacity. This calculator uses a simplified model based on the following factors:
Base rate: 0.25 in/day for still, moderate conditions. Adjustments: +0.01 in/day for every °F the water temp exceeds 75°F; +0.05 in/day per mph of wind; −0.002 in/day per percent of relative humidity. A pool cover reduces evaporation by ~95%.
A typical uncovered pool loses 1,000–2,000 gallons per month to evaporation in warm climates — equivalent to 0.5–1 inch per week. A pool cover is the single most effective way to reduce both water loss and heat loss (evaporation accounts for 70% of pool heat loss).