Cement Pack ProConcrete quantity tools

Surface protection

Surface evaporation rate

Estimate how quickly water evaporates from the concrete surface using local temperature, humidity, and wind.

Enter your measurements

Example values are prefilled. Replace them with your measurements before using the estimate. JavaScript is required to calculate.

°F

Measure the water at the concrete surface, not the temperature inside the concrete. Enter 59°F to 95°F.

°F

Measure the air near the work area. Enter 59°F to 95°F.

%

Enter a percentage from 0 to 100.

mph

Measure about 20 inches above the surface. Do not use weather-station wind speeds measured at a different height.

How it is calculated

E = [surface temperature^2.5 − (relative humidity / 100) × air temperature^2.5] × (1 + 0.4 × wind mph) × 10⁻⁶ lb/(ft²·h).

Keep the full result when using it in another calculation. Results show up to six decimal places; very small positive results use scientific notation (for example, 1e-6). No extra material for waste is added.

Measure conditions at the concrete surface

Enter the temperature of the water at the concrete surface, the nearby air temperature, relative humidity as a percentage, and wind speed measured about 20 inches above the surface. A weather-station wind reading taken at another height may not represent the input used by this model.

The equation uses Fahrenheit, a humidity fraction, and wind in miles per hour. The calculator accepts temperatures from 59°F through 95°F and humidity from 0% through 100%; it reports an error if the supplied conditions produce a negative rate.

Interpret the rate without treating it as a threshold

The example conditions produce about 0.341906 lb of water per square foot per hour. The equation accounts for surface-water temperature, air temperature, humidity, and wind; it estimates a rate for the modeled conditions rather than measuring water loss directly.

This number does not predict cracking or determine when concrete should be placed, how long it should cure, or when protection is required. Follow project requirements and applicable technical guidance for those decisions; this calculator does not provide an action threshold.

Before you use the result

  • Enter temperatures in °F and humidity as a percentage. Wind speed must be in mph, measured about 20 inches above the surface.
  • Both temperatures must be between 59°F and 95°F. The equation is not intended for temperatures outside this range.
  • The result estimates evaporation from water at the surface, not moisture loss from concrete later in curing. If the inputs produce a negative rate, the calculator reports an error rather than zero.
  • This estimate does not determine when to place concrete, how long to cure it, or when protective measures are needed. It does not predict cracking, strength, or safety.
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Estimate liquid quantity from the treated area, the exact product’s coverage per application, and the number of equal-rate applications.