Calculating Dewpoint & Relative Humidity using the Elcometer 114 Dewpoint Calculator

When measuring climatic parameters using a whirling hygrometer, also known as a sling psychrometer, once you have your wet bulb and dry bulb temperature measurements, these are then used to determine the relative humidity and dewpoint temperature.


Typically, conversion tables, like the ones supplied with the Elcometer 116 Hygrometers, are used to do this. Alternatively, a quicker and easier method is to use the Elcometer 114 Dewpoint Calculator.

Once you have your wet bulb and dry bulb temperatures, looking at the top half of the disc, on scale 1, align the wet bulb temperature with the dry bulb temperature.

Then on scale 2, locate the wet bulb temperature again, and read the measurement that it aligns with. This is your dewpoint temperature.

Secondly, looking at the bottom half of the disc, on scale 3, align the dewpoint temperature with the dry bulb temperature. This reveals your relative humidity in the window above. It’s that simple!

You’ll notice that the temperatures on the disc are in Celsius (°C), but if you require the temperatures in Fahrenheit (°F), there’s a converter located in the middle of the calculator.


Click here to download the script in English