Parametric fonts and variable fonts explained
Two ideas that often get confused: a font defined by parameters instead of fixed curves, and a font that carries several styles inside one file. Let's see what they are, how they differ and how they're made.
What a parametric font is
In a traditional font every letter is a set of hand-drawn, frozen curves: if you want a heavier weight, you redraw them. In a parametric font the letter is defined by a structure plus a set of parameters — weight, width, contrast, slant, serifs. Change a value and the character redraws itself.
The benefit is consistency: one rule applied to all glyphs at once, instead of a thousand manual tweaks. It's a way of thinking about a font as a system, not a collection of drawings.
What a variable font is
A variable font is a format (an extension of OpenType) that packs an entire family into a single file. Instead of exporting Thin, Light, Regular, Bold and Black as separate files, you ship one with one or more variation axes along which the font can change continuously.
The most common standard axes:
- Weight (wght) — from thin to black.
- Width (wdth) — from condensed to extended.
- Slant / Italic — slant and italic.
- Optical size (opsz) — adapts the design to the size it's used at.
On the web it means loading one file instead of six, and being able to use any intermediate weight via CSS with font-variation-settings.
What's the difference
They live on two different planes and only partly overlap:
- Parametric is a design method: how you define and draw the font.
- Variable font is a distribution format: how the finished font is saved and used.
You can design parametrically and export a normal static OTF. And you can produce a variable font starting from a traditional editor. But the two pair well: a parametric workflow naturally generates the extremes and intermediate weights a variable font needs.
Interpolation between masters
The mechanism that ties the two worlds together is interpolation. You define two (or more) masters — the extremes, say a Thin and a Black — and the system automatically computes every weight in between, blending the shapes point by point.
For this to work, the masters must be compatible: the same number of points, in the same order, on every glyph. That's the main technical constraint of interpolation, and it's also why a parametric approach helps — the shared structure keeps the masters aligned by construction.
In practice. With a parametric editor you define the extremes once and get every intermediate variant, without redrawing anything — exactly the logic of a variable font.
How to make a parametric font
The workflow, in short:
- Skeletons — define the structure of each glyph instead of drawing its curves.
- Parameters — adjust weight, width, contrast and slant; the engine generates the outlines in real time.
- Masters — set two extremes and get the intermediate weights by interpolation.
- Export — generate a standard OTF file, installable anywhere.
That's the workflow of Apice Studio, which does all of this in the browser. For the full process from blank page to font file, see the guide how to create a font from scratch.
FAQ
Are variable fonts and parametric fonts the same thing?
No. Parametric is the method you design the font with; variable font is the format you distribute it in. They often go together, because a parametric workflow naturally produces the axes and weights a variable font uses.
Do variable fonts work on the web?
Yes, they're supported by all modern browsers. You load a single file and control weight, width and other axes via CSS with font-variation-settings.
What does it mean for masters to be compatible?
To interpolate, every glyph must have the same number of points in the same order across all masters. If the structure matches, the system can compute the intermediate shapes. A parametric approach keeps this compatibility by construction.
Can I export a parametric font as a normal OTF?
Yes. You can design parametrically and export a single weight as a static OTF, or several weights. With Apice Studio, export is a standard OTF that opens in any application.