How can one calculate the original concentration from dilution?

To calculate the original concentration from dilution, use the formula: C1V1 C2V2. Where C1 is the original concentration, V1 is the original volume, C2 is the final concentration, and V2 is the final volume. Rearrange the formula to solve for C1: C1 (C2V2) / V1. This will give you the original concentration.