Pool evaporation calculator
PRODaily gallons lost to evaporation.
Short answer: gal/day = surface × (in/wk ÷ 7) × 0.623. 512 sq ft × 1.5 in/wk = 68 gal/day. Enter your measurements above and the pool evaporation calculator returns the quantity, unit conversions and an estimated cost instantly, in imperial or metric — no sign-up needed.
What do you need to measure?
What is the answer?
Gallons / day
68
Gallons / week
478
How does the pool evaporation calculator work?
gal/day = surface × (in/wk ÷ 7) × 0.623.
What does a worked example look like?
512 sq ft × 1.5 in/wk = 68 gal/day.
What do people ask most?
›Normal rate?
¼" to 2" per week depending on wind, sun and humidity.
Which pool calculator should you use next?
Where can you learn more?
Read field notes on estimating and materials, or browse every calculator we make.