How to Use the Water Evaporation Rate Calculator

A Water Evaporation Rate Calculator estimates how much water will evaporate from a given surface area per day based on temperature, humidity, and wind speed.

What It Does:

This tool uses a simplified empirical formula to help estimate daily water loss (in liters/day) from surfaces like pools, tanks, or reservoirs under typical environmental conditions.

Inputs Required:

• Surface Area (m²): Total exposed area of the water body.
• Air Temperature (°C): Ambient air temperature.
• Relative Humidity (%): Current atmospheric humidity (0–100%).
• Wind Speed (m/s): Wind velocity across the water surface.

Steps to Use:

1. Enter the water surface area in square meters.
2. Input the temperature, humidity, and wind speed.
3. Click “Calculate Evaporation Rate”.
4. The calculator displays daily water loss in liters.

This is particularly useful for:

• Gardeners managing irrigation
• Pool owners estimate refill schedules
• Engineers planning reservoir maintenance
• Researchers modeling water resource loss

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Evaporation Rate Calculator FAQ

Q1: How accurate is this evaporation rate?
A: The result is an approximation using a simplified formula. Real-world conditions like solar radiation, shading, and pressure changes may affect accuracy.

Q2: What is the formula being used?
A: The calculator uses a modified version of an empirical equation:
Evap Rate (m/day) = 0.1 × (25 + T) × (100 − RH) × (1 + 0.1 × Wind) / 10,000

Q3: Why is the result in liters/day?
A: It's a familiar unit and easier to apply for tasks like estimating refilling needs or water conservation planning.

Q4: Can this be used for indoor evaporation (e.g. humidifiers)?
A: Not reliably. Indoor environments have controlled factors and typically require more detailed psychrometric data.

Q5: Is wind speed important?
A: Yes. Wind increases evaporation by carrying away saturated air, allowing more moisture to escape.

Q6: Does it consider solar radiation?
A: Not directly. This version assumes a general average outdoor environment. For solar-specific impact, advanced models or sensors are needed.