Evaporation Rate Calculator

Estimate evaporation rate and water loss from air temperature, relative humidity, wind speed, water surface area, sun exposure, and time. This calculator can help estimate water loss from pools, ponds, tanks, rain barrels, gardens, and open water surfaces.

Calculate Evaporation Rate

Evaporation Estimate = base rate × temperature factor × humidity factor × wind factor × sun factor × area × time
Your result will appear here.

How the evaporation rate calculator works

Temperature:
Warmer air can hold more moisture, which usually increases the potential for evaporation.

Humidity:
Dry air increases evaporation because the air has more capacity to take up water vapor.

Wind speed:
Wind can increase evaporation by moving humid air away from the water surface.

Surface area and time:
A larger exposed water surface and longer time period create more total water loss.

Why use an evaporation rate calculator?

An evaporation rate calculator is useful for pools, ponds, reservoirs, rain barrels, livestock tanks, garden beds, irrigation planning, water storage, landscaping, and estimating water loss during hot, dry, or windy weather.

This is a rough estimate. Real evaporation depends on solar radiation, water temperature, air temperature, humidity, wind, pressure, surface mixing, covers, shade, and local microclimate.

What your result means

Your result estimates evaporation depth and total water loss over the selected surface area and time period. Higher depth means more water is evaporating from each square foot or square meter of exposed surface.

Evaporation reduction tips

Frequently asked questions

How do you estimate evaporation rate?

This calculator uses a rough base evaporation rate adjusted by temperature, humidity, wind speed, sun exposure, water surface type, area, and time.

What weather causes high evaporation?

Hot, dry, sunny, and windy weather usually causes the highest evaporation rates.

How much water can a pool lose to evaporation?

Pool water loss can vary widely, but hot, dry, windy weather can remove noticeable water depth over a few days.

Does humidity reduce evaporation?

Yes. Higher humidity means the air is already holding more water vapor, so evaporation usually slows down.