Welcome to the Dew Point Calculator

Use the sliders to explore combinations of temperature (T), relative humidity (RH), and dew point (DP) to compare the preservation quality of your environment. Knowing the dew point can help achieve long-term preservation of collection materials for libraries, museums, and archives. To report on your storage environment use a datalogger to record data and eClimateNotebook® to analyze it.

Click to Solve for:

Temperature

% RH

Dew Point

Preservation Evaluation

Type of Decay	Environment Rating	Preservation Metric
Natural Aging	RISK	PI	44
Mechanical Damage	OK	% EMC	9.3
Mold Risk	GOOD	Days to Mold	No Risk
Metal Corrosion	OK	% EMC	9.3

Record and Compare Values

T	RH	DP	PI	Days to Mold	EMC

Temperature Scale: °F °C

The dew point temperature determines what combinations of temperature and RH will be possible in the storage environment. At a constant dew point, when the temperature goes up, the RH goes down and when the temperature goes down, the RH goes up. Controlling the dew point is key to managing the risk of material decay. What's your dew point? If you know the T & RH in your space you can use the DP Calculator to get the DP. If your building does not have humidification or dehumidification, the indoor dew point is the same as the outdoor dew point.