Calculate coefficient of moisture expansion, change in length, original length, or moisture content by entering any 3 of the 4 values.
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Coefficient Of Moisture Expansion Formula
The coefficient of moisture expansion relates a material’s length change to its original length and the change in moisture content. The calculator uses the following main formula:
Rearranged formulas used to solve for the missing value:
- CME = coefficient of moisture expansion
- ΔL = change in length
- L0 = original length
- ΔM = change in moisture content as a decimal
The calculator accepts the change in moisture content as a percent, then converts it to a decimal before applying the formula. For example, 5% is used as 0.05 in the calculation.
Length values are converted to inches internally so that the change in length and original length use the same base unit. After the calculation, the result is converted back to the unit selected in the input field.
You can enter any three values to solve for the fourth: coefficient of moisture expansion, change in length, original length, or change in moisture content.
Length Unit Conversions Used
The calculator converts length inputs to inches before calculating.
| Unit | Conversion to inches |
|---|---|
| in | 1 in = 1 in |
| ft | 1 ft = 12 in |
| cm | 1 cm = 0.393701 in |
| m | 1 m = 39.3701 in |
Moisture Change Percent to Decimal
Moisture content must be used as a decimal in the formula.
| Moisture change entered | Decimal used in formula |
|---|---|
| 1% | 0.01 |
| 5% | 0.05 |
| 10% | 0.10 |
| 15% | 0.15 |
Example Problems
Example 1: Calculate coefficient of moisture expansion
Suppose a material has an original length of 40 in, a change in length of 0.08 in, and a moisture content change of 5%.
The coefficient of moisture expansion is 0.040000.
Example 2: Calculate change in length
Suppose the coefficient of moisture expansion is 0.03, the original length is 2 ft, and the moisture content change is 8%.
First convert 2 ft to inches:
Then calculate the change in length:
The change in length is 0.0576 in.
FAQ
What does the coefficient of moisture expansion mean?
The coefficient of moisture expansion describes how much a material expands or contracts for a given change in moisture content. A larger value means the material changes length more for the same moisture change.
Why does the calculator convert moisture percent to a decimal?
The formula uses moisture change as a ratio, not as a whole percent number. If the moisture content changes by 5%, the formula uses 0.05. Using 5 instead of 0.05 would make the result 100 times too large or too small, depending on which value you are solving for.
Do the length units have to match?
Yes. The change in length and original length must be in compatible units before applying the formula. The calculator handles this by converting both length values to inches internally, then converting the calculated result back to the selected unit when needed.