A multimode electronic measuring instrument is provided that includes a ratiometric mode of operation. During the ratiometric mode, a desired dimension is established as a stored reference dimension "X.sub.ref". After the reference dimension is stored in memory, subsequent ratiometric measurement readouts will equal a current measurement distance "X.sub.curr" divided by the reference dimension X.sub.ref. A ratiometric measurement according to this invention indicates the relationship of a current dimension to another readily changed (reference) dimension. The ratiometric mode of operation can be implemented in combination with conventional function caliper functions to provide a multimode caliper having a simple and intuitive user interface. Setting the reference dimension and interpreting the ratiometric measurement display are particularly easy, to facilitate intuitive understanding and operation.