Design Nomenclature / Systems & Spec
Modular scale
Also called type scale, ratio scale, typographic scale
A set of sizes generated by multiplying a base repeatedly by a fixed ratio — 16 at 1.25 gives 20, 25, 31.25 — so every step relates to every other by the same interval. The ratio is a constraint, not evidence of quality; the useful part is ending up with fewer sizes.
In practice
Sold as harmony borrowed from music. What it actually buys is a defensible reason to say no to a twelfth heading size.
Not to be confused with
- Spacing scaleThe restricted set of gap values a system permits — usually a base unit stepped geometrically or in multiples of four or eight — applied to padding, margin, and gaps. Rounding to whole pixels matters more here than ratio purity: a 1.25 ratio from 4 produces values nothing renders cleanly.
- ProportionThe relation of one dimension to another — within an element, between elements, or between an element and the whole. Proportion is a ratio and survives resizing; scale does not. A proportional system fixes a small set of allowed ratios so that sizes relate rather than merely differ.