Enter the current amount (after dilution) and the dilution fraction (the fraction of the original remaining after dilution; e.g., 0.65 means 65% remains) into the Reverse Dilution Calculator. The calculator will evaluate and display the original amount (before dilution).
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Reverse Dilution Formula
The following formula is used to calculate the original amount (reverse dilution result).
RD = CA / DF
- Where RD is the original amount/concentration (before dilution)
- CA is the current amount/concentration (after dilution)
- DF is the dilution fraction (remaining fraction), defined as DF = CA / RD (typically between 0 and 1 for a dilution)
To calculate the reverse dilution (original amount), divide the current amount by the dilution fraction.
Note: Some sources define “dilution factor” as a fold-dilution value F = (final volume) / (aliquot volume), which is usually > 1. If you have that definition, then DF (this page) = 1 / F and RD = CA × F.
How to Calculate Reverse Dilution?
The following example problems outline how to calculate Reverse Dilution.
Example Problem #1:
- First, determine the current amount.
- The current amount is given as: 400.
- Next, determine the dilution fraction.
- The dilution fraction is provided as: 0.65.
- Finally, calculate the Reverse Dilution using the equation above:
RD = CA / DF
The values given above are inserted into the equation below and the solution is calculated:
RD = 400 / 0.65 = 615.385
Example Problem #2:
For this problem, the variables required are provided below:
current amount = 300
dilution fraction = 0.75
Test your knowledge using the equation and check your answer with the calculator above.
RD = CA / DF = ?
