Online Dew Point Calculator

Nothing to download, works on a Mac or PC.

The Dew Point Calculator is now available online! Visit to explore its features.

The Dew Point Calculator is a web-based application, so no download is necessary. In addition, the Dew Point Calculator can be used with any web browser (Firefox, Internet Explorer, etc.) on a Macintosh or a PC.

To learn more about how the Dew Point Calculator can be applied to environmental monitoring, refer to the following articles: Understanding Dew Point, Why is Dew Point Important for Managing my Environmental Conditions?, and Winter Dryness and Its Effects on Collections.

Online Dew Point Calculator

Visit to start using the online Dew Point Calculator!

DewPoint Calculator

(Windows only)

What conditions will provide the longest life for your collection, prevent mold growth, and decrease the risk of mechanical decay?

DewPoint Calculator illustrates the interrelation of temperature, RH, and dew point. Enter values for any two of these three elements, and the software application will provide the third, allowing you to explore this three-way relationship in a hypothetical storage or display environment.

DewPoint Calculator

Will condensation occur if an object is brought directly into a work room?

DewPoint Calculator calculates the risk of condensation, too. Determine the optimum RH for your work room environment or what the temperature of an object must be to prevent condensation from forming when it leaves the storage environment.


DewPoint Calculator is included in Climate Notebook 3.1, but it's also available at no charge as a stand-alone application. Try it out! Download DewPoint Calculator.


Preservation Calculator

(Windows only)

How good is your storage environment? How fast is your collection deteriorating? Will your current storage conditions encourage mold growth?

Preservation Calculator is a planning and analysis tool for collection storage environments in libraries, archives, and museums. Use it to:

  • learn how temperature and RH affect organic objects in storage
  • evaluate a given storage condition
  • compare one storage condition to another
  • plan new storage conditions

Organic materials (carbon-containing substances such as plastics, dyes, paper, plants, and animal products) make up a large proportion of cultural property collections. Preservation Calculator shows how temperature and humidity combine to influence the rate of decay of organic objects. It is concerned with two forms of decay: natural aging (caused by spontaneous chemical change within the material) and mold damage.

Download Preservation Calculator
The self-extracting file “wwwprescalc.exe” will automatically install the program on your local computer. Preservation Calculator runs with Windows® 95, 98, NT, ME, 2000, and XP. (Not available for the Mac.)


Preservation Calculator for Photo Storage

(Windows only)

Preservation Calculator for Photo Storage is a special version of Preservation Calculator designed for planning or evaluating storage conditions specifically for photographic objects, including negatives, prints, and photo albums. Use it to make informed decisions on where and where not to store photos. Prevent damage from mold, rapid fading, stickiness, or other environment-related problems by understanding the effects of temperature and humidity on photographic objects.

Preservation Calculator for Photo Storage has all of the features included in Preservation Calculator, and it also has an indicator light to show the user whether or not conditions are recommended for photos. English, German, and Spanish versions are available.