Is dilution ratio the same as dilution factor?

Dilution ratio is not the same as dilution factor. However, the difference between these two terms is so miniscule that it is almost negligible. This often results in the two terms being used interchangeably.   Dilution ratio refers to a simple dilution, in which a unit volume of a solute is combined with a desired volume of solvent. Dilution factor on the other hand refers to the ratio of the volume of the initial concentrated solute to the total volume of the final diluted solution.

In more concrete terms: 

Dilution ratio of 1:5 would indicate 1 part solute + 5 parts solvent = 6 parts in total. The final volume is calculated as the sum of both sides. 

Dilution factor of 1:5 would indicate 1 part solute dissolved in 5 parts solvent = 5 parts in total. The final volume is calculated as part volume x total parts.