How this calculator works
A dilution factor compares total volume with the aliquot of stock. The solvent-to-stock ratio is one less. The distinction avoids the ambiguity of phrases such as one-to-ten dilution. Volumes are assumed additive. A factor of one means no dilution and zero diluent. Repeated steps multiply their individual factors.
Formula
D = (Vstock + Vdiluent)/Vstock = Vfinal/Vstock. Diluent-to-stock ratio = D - 1.
Worked example
One mL of stock plus 9 mL diluent gives factor 10 and diluent-to-stock ratio 9. A 10 mL final mixture at factor 5 needs 2 mL stock and 8 mL diluent.
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Frequently asked questions
Does 1:10 always mean factor ten?
Wording varies. State whether the second number refers to diluent or total mixture.
Does a factor of ten increase concentration?
No. It reduces the stock concentration to one tenth.
How do serial factors combine?
Multiply them. Three tenfold steps give a total factor of 1000.