Work out how many fold a solution was diluted — from aliquot and final volume, or from stock and final concentration — and see the equivalent 1:X mixing ratio.
Pick what you know, enter the two values and the result updates as you type.
The dilution factor is the fold-change of a dilution: final volume divided by the aliquot of stock you put in (DF = V₂ ÷ V₁). Diluting 1 mL up to 10 mL is a 10× dilution. Multiply a measured concentration by the factor to recover the original — which is why assay results are reported together with their dilution factor.
Because the solute is conserved, the same factor also equals stock concentration divided by final concentration (DF = C₁ ÷ C₂). A 5 M stock measured down at 0.2 M was diluted 25×. This direction is handy when you know what a dilution produced but not how it was mixed.
The factor counts total parts; the common 1:X label convention counts added diluent. A 10× dilution is one part stock plus nine parts diluent — a 1:9 ratio — while "1:10" on a product label is an 11× dilution. The calculator prints both forms so the conversion is never done in your head.
Dilution factors multiply: a 10× dilution followed by a 5× dilution is a 50× dilution overall. That is the arithmetic behind serial dilutions, where the same factor applied n times gives DFⁿ overall — see the serial dilution calculator to plan one.
From volumes, the factor is the final volume divided by the aliquot volume; from concentrations, the stock concentration divided by the final concentration. Volumes may be entered in different units — they are converted to liters before dividing — and concentrations must share a unit family for the same reason.
The equivalent mixing ratio shown is 1 : (DF − 1), the added-diluent convention used on product labels. The calculator is tested against the worked examples on this page before every release.
This calculator is for general laboratory reference. Verify critical preparations against your protocol and a qualified professional.
Short answers to the questions people ask most about dilution factors.