What is the dilution factor?
The dilution factor (DF) tells you how many times a stock solution must be diluted to reach a desired target concentration. It is the ratio of the stock concentration to the final concentration. A DF of 10 means a 1:10 dilution — one part stock plus enough diluent to make ten total parts.
How to use this calculator
Enter the concentration of your stock solution and the target (final) concentration you want to achieve. Use any consistent units (M, mM, mg/mL, %, etc.) for both values. Optionally enter the final volume you want to prepare and the calculator will tell you how much stock and how much diluent to combine.
The formula explained
The core equation is $$\text{DF} = \frac{\text{C}_{\text{stock}}}{\text{C}_{\text{final}}}$$ Because the same units appear in the numerator and denominator, the dilution factor is unitless. To prepare a specific volume, take \(V_{\text{stock}} = V_{\text{final}} / \text{DF}\) of stock and add diluent up to \(V_{\text{final}}\).
Worked example
You have a 100 mM stock and need 10 mM. $$\text{DF} = 100 / 10 = 10$$ a 1:10 dilution. To make 50 mL: \(V_{\text{stock}} = 50 / 10 = 5\) mL of stock, then add 45 mL of diluent.
FAQ
What does 1:10 mean? It means the final solution is 10 times more dilute than the stock — one part stock in ten total parts.
Can I use different units? Yes, as long as both concentrations use the same unit. The ratio cancels the units out.
What if my target is higher than my stock? You cannot dilute up; the DF would be less than 1, meaning you would need to concentrate the solution instead.
