Fluid Type Scale Calculator

Generate font size variables for a fluid type scale with CSS clamp.

Overview

Customize everything, grab the output CSS, and drop it into any design system. Share the URL with your team members or use it to document your CSS.

Features

Fully customizable parameters for everything:
- Baseline min/max font size, screen width, type scale.
- The names of the steps in your type scale.
- The prefix to use for the variable names.
- The max number of decimal places in the output.
- Whether to show output in rems or pixels.
- The resolved pixel value of 1rem.
Output CSS variables for fluid font sizing.
Live preview table. Pick a font and enter some sample text to fine-tune the results.
Link sharing.

Link Sharing

Note: This is NOT a developer API.

The /calculate route accepts the following query parameters and types. All parameters are optional, meaning you can technically navigate to just /calculate and it'll return a valid response. If a parameter is not specified, it will fall back to the default for that value (this is the case for all parameters except useRems; see table below). If a parameter's constraints are violated, you will be redirected to an error page.

Param	Description	Type	Validation constraints	Default if not specified
`minFontSize`	The minimum font size for the base step	`number`	Non-negative	`16`
`minWidth`	The screen width corresponding to the minimum font size	`number`	Non-negative and `< maxScreenWidth`	`400`
`minRatio`	The type scale ratio for the minimum font size of each step	`number`	Non-negative	`1.25`
`maxFontSize`	The maximum font size for the base step	`number`	Non-negative	`19`
`maxWidth`	The screen width corresponding to the maximum font size	`number`	Non-negative and `> minScreenWidth`	`1280`
`maxRatio`	The type scale ratio for the maximum font size of each step	`number`	Non-negative	`1.333`
`steps`	A comma-separated list of names for your type scale steps, in ascending order of font size	`string`	Comma-separated list. Step names must be alphanumeric, with no spaces.	`sm,base,md,lg,xl,xxl,xxxl`
`baseStep`	The name of the base step	`string`	Must exist in `steps`	`base`
`prefix`	The naming convention to use for the output CSS variables	`string`	Non-empty	`font-size`
`includeFallbacks`	Whether to include fallback variables in the CSS output for browsers that don't support clamp.	`on`, `true`, or `false`	An empty value will be treated as `true`. Omission implies `false` (fallbacks are not included).	`false`
`useRems`	Whether to use rems for font sizing.	`on`, `true`, or `false`	An empty value (e.g., `useRems`) will be treated as `true`. Omission implies `false` (pixels will be used).	`on`
`remValue`	The computed pixel value of `1rem`. Useful if your app changes the root font size (e.g., with the popular `62.5%` font size trick). Note: This parameter has no effect if `useRems` is omitted.	`number`	Integer. Min: `1`.	`16`
`decimals`	The number of decimal places to round the output to.	`number`	Non-negative integer. Max `10`.	`2`
`previewFont`	The font family to render in the preview.	`string`	Spaces must be escaped (e.g., `Libre+Baskerville`). The font must be a valid Google Font. Custom fonts are not supported.	`Inter`
`previewText`	The text to render in the preview table.	`string`	Spaces must be escaped (e.g., `Libre+Baskerville`). Must be a non-empty string if specified.	`Almost before we knew it, we had left the ground`
`previewWidth`	The width to simulate in the preview table.	`number`	Integer. Min: `0`. Max: `1920`.	`1280`

Example URL: https://www.fluid-type-scale.com/calculate?minFontSize=15&minWidth=400&minRatio=1.25&maxFontSize=17&maxWidth=1280&maxRatio=1.333&steps=sm%2Cbase%2Cmd%2Clg%2Cxl%2Cxxl%2Cxxxl&baseStep=base&prefix=font-size&decimals=2&useRems=on&remValue=10&previewFont=Libre+Baskerville&previewText=Testing+123&previewWidth=420

Tech Stack

Fluid Type Scale Calculator runs on Next.js.

React
TypeScript
Sass + CSS Modules

Running Locally

Clone the repo.
Run yarn to install dependencies.
Run yarn dev and visit localhost:3000 to view the app.

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Learn More

Creating a Fluid Type Scale with CSS Clamp, a deep dive I wrote on this topic. The technique covered in the article is the basis for this app.
Generating font-size CSS Rules and Creating a Fluid Type Scale by Stephanie Eckles
Consistent, Fluidly Scaling Type and Spacing by Andy Bell

AleksandrHovhannisyan/fluid-type-scale-calculator

AleksandrHovhannisyan

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