Equivalent Ratios Calculator

This page opens the ratio calculator in scale mode: enter a ratio and a factor, and both sides are multiplied by it to produce an equivalent ratio. Scaling 2 : 3 by 4 gives 8 : 12; scaling it by 2.5 gives 5 : 7.5, which the calculator also rewrites as the whole-number pair 10 : 15.

Because scaling never changes the underlying relationship, equivalent ratios are how you adapt a fixed recipe, mix or mortar formula to a different batch size. The step list shows each multiplication separately, and decimal factors are computed exactly rather than through floating-point shortcuts.

Use it to double or halve ingredient lists, to convert a 1 : 50 model scale to real dimensions, or to generate a table of equivalent ratios for a classroom exercise — each run produces one equivalent pair plus its whole-number form when decimals appear.