Wood Moisture Equilibrium Calculator

Calculate the Equilibrium Moisture Content (EMC) of wood from temperature and humidity using the Hailwood-Horrobin equation, plus dimensional change and acclimation time.

Inputs

Temperature (F)

Relative humidity (%)

Current wood MC (%)

Board thickness (in)

Board width (in)

Tangential shrinkage %/MC% (0=avg)

Tab to move between fields

Results

Equilibrium MC (%)

9.2

MC change needed (%)

2.8

Current MC (%)12

Width change (in)0.05

Dimensional change (%)0.77

Estimated acclimation (days)17

Interior furniture target MC (%)7

EMC vs interior target (%)2.2

Risk LevelModerate — allow full acclimation

How to Use This Calculator

Enter the ambient Temperature in °F and Relative Humidity percentage where the wood will be installed.
Enter the Current Wood Moisture Content from a moisture meter reading.
Enter the Board Thickness and Width in inches for dimensional change calculations.
Review Equilibrium MC to know the target moisture content and MC Change needed.
Check Width Change in inches and Acclimation Days to plan proper wood conditioning before construction.

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