Dilution Factor Calculator

The dilution factor is computed using one of two equivalent approaches:

Method 1 — From Volumes:

DF = V_final / V_sample

Where V_final is the total volume after dilution and V_sample is the volume of sample (or stock) used. For example, adding 1 mL of serum to 9 mL of diluent gives V_final = 10 mL, V_sample = 1 mL, and DF = 10.

Method 2 — From Concentrations:

DF = C_stock / C_dilute

If you know the concentrations before and after dilution, their ratio directly gives the dilution factor. A 10 M stock diluted to 0.5 M has DF = 20.

The two methods must give the same result (conservation of solute). The dilution ratio is often expressed as "1:DF" — for example, a dilution factor of 10 is written as "1:10" (one part sample to nine parts diluent, making ten parts total).

To recover the original concentration from a diluted measurement: C_original = C_measured × DF. This is the most important practical application of the dilution factor in analytical and clinical chemistry.

Note the distinction between "1:10 dilution" (1 part sample + 9 parts diluent = DF of 10) and "1+10 dilution" (1 part sample + 10 parts diluent = DF of 11). The former is standard in most chemistry and biology contexts.

A dilution factor of 1 means no dilution occurred. A DF of 10 means the solution is 10 times less concentrated than the original. Large dilution factors (100, 1000, etc.) indicate highly diluted samples. In clinical chemistry, common dilution factors are 2, 5, 10, 20, and 100 — depending on the analyte concentration and assay range.

The dilution ratio output shows the result as a rounded integer for easy expression (e.g., "1:10"). For non-integer ratios, express as a decimal (e.g., DF = 2.5 means 1:2.5 dilution).