A ratio compares quantities. In a same-unit ratio of 2 : 3, the first quantity is 2/3 of the second, but it is 2/5 of the combined total. These are different comparisons.

Choose “Different units” for rates such as cups per cookie. Shares of a combined total then have no meaning, and are not shown. To split a total, every ratio part must use the same units. For physical mixes, use the specified weight or volume ratio: this tool does not convert between them.

Nonnegative rational quantities, two to six parts, at most 24 input digits. Fractions remain exact. Optional decimals are rounded to twelve significant digits and marked ≈ when rounded. A ratio with a zero second quantity has no finite quotient. Proportion denominators B and D must be positive.

Splitting returns exact quantities, not rounded allocations of indivisible objects or money. Convert units and apply a suitable allocation rule separately.

Reference: OpenStax: ratios and proportions. For calculations with a single fraction, use the fraction calculator.