Practical AtlasIndependent referenceFree online tool
Humidity and dew point calculator
Turn room temperature and humidity into the dew point, the surface temperature at which windows fog and damp problems begin.
Read humidity in context.
Calculate dew point and classify the current relative-humidity reading.
COMMON WAYS TO ASK
- What should indoor humidity be?
- Why do my windows fog up?
- Calculate dew point
What this calculator tells you.
Enter the room temperature and relative humidity to get the dew point, which is the surface temperature at which condensation starts. That single number explains most damp-window and mold complaints.
A warm, humid living room
Questions people ask next.
Why does the same humidity feel different in winter?
Relative humidity is relative to temperature. Cold air holds less moisture, so 60% in a cold room is far less water than 60% in a warm one, and it condenses at a much lower surface temperature.
Is condensation on windows a humidity problem or a window problem?
Both are possible. Condensation appears when a surface falls below the dew point, so it can be fixed by lowering indoor moisture or by raising the surface temperature.