Wood Moisture Content Calculator

This calculator computes the moisture content of wood, using the oven-dry method. A calculator for the equilibrium moisture content is also included. Units are in the imperial system. 
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CalculationsThere are two ways to calculate the moisture content of wood:
1) Simple Moisture Content 
While directly measuring the water mass in a piece of wood is nearly impossible, it can be determined by calculating the weight difference between the wood's wet state and its bone-dry state. This method of calculating moisture content is known as the oven-dry method.
Inputs
﻿﻿m_wet
:100lb​
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﻿﻿m_dry
:75lb​
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Output
﻿﻿MC
:0.3333333333333333​
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The equation for moisture content, as a percentage, is given by:
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MC(%)=mwet−mdrymdry×100MC(\%) = \dfrac{m_{\text{wet}} - m_{\text{dry}}}{m_{\text{dry}}} \times 100MC(%)=mdry​mwet​−mdry​​×100
Where:
﻿﻿mwet​
 is the wet weight of the wood, in pounds ﻿(lb)
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﻿﻿mdry​
 is the oven-dried (or bone-dried) weight of the wood, in pounds ﻿(lb)
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2) Equilibrium Moisture Content
The moisture content of wood specimens can also be estimated based on the temperature and relative humidity of the environment, reaching a point called the Equilibrium Moisture Content (EMC) after enough time. 
Inputs
﻿﻿T
:70degF​
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﻿﻿h
:0.15​
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Outputs
﻿﻿W
:382​
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﻿﻿K
:0.82​
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﻿﻿K1
:5.9361​
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﻿﻿K2
:2.63504​
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﻿﻿EMC
:0.0354163041304521​
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The equation for equivalent moisture content, as a percentage, is given by:
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EMC(%)=1800W[Kh1−Kh+K1Kh+2K1K2K2h21+K1Kh+K1K2K2h2]EMC(\%) = \dfrac{1800}{W}\left[ \dfrac{Kh}{1-Kh}+\dfrac{K_1Kh + 2K_1K_2K^2h^2}{1 + K_1Kh + K_1K_2K^2h^2}\right]EMC(%)=W1800​[1−KhKh​+1+K1​Kh+K1​K2​K2h2K1​Kh+2K1​K2​K2h2​]
Where:
﻿﻿h
 is the relative humidity of the environment, as a percentage ﻿(%)
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﻿﻿T
 is the temperature of the environment, in Fahrenheit ﻿(F)
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﻿﻿W,K,K1​,K2​
 are parameters given by:
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W=330+0.452T+0.00415T2K=0.791+0.000463T−0.00000844T2K1=6.34+0.000775T−0.0000935T2K2=1.09+0.0284T−0.0000904T2W = 330 + 0.452T + 0.00415T^2 \\K = 0.791 + 0.000463T - 0.00000844T^2 \\K_1 = 6.34 + 0.000775T - 0.0000935T^2 \\K_2 = 1.09 + 0.0284T - 0.0000904T^2 W=330+0.452T+0.00415T2K=0.791+0.000463T−0.00000844T2K1​=6.34+0.000775T−0.0000935T2K2​=1.09+0.0284T−0.0000904T2
For most practical uses this formula can be applied to any species.
ExplanationMoisture content significantly affects the properties of wood in several ways:
Wood expands and contracts with changes in moisture content. Higher moisture levels cause wood to swell, while lower levels lead to shrinkage. 
Increased moisture generally reduces the strength and stiffness of wood, making it less suitable for structural applications. Dry wood tends to be stronger and stiffer compared to wet wood.
The weight of wood increases with higher moisture content. This is particularly important in applications where weight is a critical factor, such as during construction.
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Wood swells with higher moisture [source]
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