This exposes the hidden structure.
These tools expose the structure behind something that usually gets judged by eye: line length, hierarchy, wrapping, spacing or fit.
Type, Layout & Effects
Try these fonts together.
Type two font family names and judge the pairing on real sample copy.
Fonts
Pairing preview
Tools for the annoying bits.
Use the second font for supporting copy. The point is to judge contrast in voice, width and texture, not chase a mathematical score.
Type any installed font family name into the fields.
Useful to know
Four things worth knowing.
Neat maths can still look wrong.
The mathematically neat answer can still look wrong. Typography and layout have an optical component that a counter cannot see.
Check it where people see it.
Judge it at the size it will actually be used. Typography and spacing are partly optical.
Optical judgement still matters.
Judge the result at its final size. A headline that works in a desktop editor can fall apart on a phone or projected slide.