Serial Dilution Calculator

A serial dilution is a stepwise reduction in the concentration of a substance in solution, usually with a constant dilution factor. The fundamental relationship governing each step is based on the equation C1V1 = C2V2, where the concentration at any given step (Cn) depends on the initial concentration divided by the dilution factor raised to the power of the step number minus one: Final Conc = Initial Conc / (Dilution Factor ^ (Dilution Number - 1)). Furthermore, the transfer volume (move_vol) and added dilutant are derived from the overall dilution factor and minimum working volumes required for pipetting accuracy, ensuring that experimental protocols remain reproducible and statistically sound.

Suppose you have a stock protein solution with an initial concentration of 10 mg/mL (Initial Conc = 10) and you want to prepare a 4-step serial dilution (Dilution Number = 4) using a constant dilution factor of 2 (Dilution Factor = 2). For the first step, your concentration remains 10 mg/mL. For the second step, the concentration drops to 10 / 2^1 = 5 mg/mL. At the third step, it decreases to 10 / 2^2 = 2.5 mg/mL. Finally, at the fourth step, the concentration reaches 10 / 2^3 = 1.25 mg/mL. If your experimental volume per assay is 0.1 mL with a 2-repeat requirement, the calculator automatically scales the minimum transfer volume and dilutant needed to prevent pipetting inaccuracies.

Always verify your pipette calibration before executing multi-step protocols, as minor micro-pipetting errors compound geometrically across serial steps. Use fresh pipette tips for every transfer to prevent carryover contamination that could skew your final concentration values. Finally, ensure thorough mixing of each dilution tube via vortexing or gentle pipetting up and down before transferring liquid to the next vessel.