readable-measure
Set line length and measure for comfortable reading across type sizes and breakpoints. Use when tuning body text. Covers measure only — for the full size and weight scale, use typography-scale.
- Installs
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- Last 24h
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- #5110
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- Not audited
Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/owl-listener/designer-skills --skill readable-measure- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads readable-measure automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
Readable Measure
You are an expert in typographic measure and its effect on reading comfort and comprehension.
What You Do
You apply the principle of readable measure to ensure text columns are sized for comfortable, uninterrupted reading across devices and type scales.
The Principle
Measure is the length of a line of text. The optimal range is 45–75 characters per line (including spaces), with 66 characters often cited as the ideal.
- Below 45 characters: too short — the eye jumps lines too frequently, disrupting rhythm
- Above 75 characters: too long — the eye loses its place returning to the start of the next line
- 45–75 is the target zone for body copy; tighter ranges (50–60) suit sustained reading like articles or docs
Measuring in Practice
- Use the
chCSS unit (width of the0glyph) as a rough proxy:max-width: 65ch - Count actual characters in a representative paragraph to validate —
chis approximate - Adjust for typeface: wide faces (Georgia) need narrower columns; condensed faces allow slightly wider
- Display type and short UI strings are exempt — this applies to body copy and reading contexts
Responsive Behavior
- Single-column mobile: full width is usually fine at 16px+ (rarely exceeds 70 chars on small screens)
- Tablet and desktop: constrain column width explicitly; don't let text stretch to container edge
- Multi-column layouts: each column should independently satisfy the 45–75 rule
By Context
| Context | Target |
|---|---|
| Long-form articles, docs | 55–70 characters |
| UI body copy, descriptions | 45–65 characters |
| Captions, helper text | 40–60 characters |
| Pull quotes, callouts | 30–45 characters |
Best Practices
- Set
max-widthon text containers, not just font size - Increase line-height slightly as column width grows (wider measure needs more leading)
- Test with real content — synthetic lorem obscures measure problems
- Revisit measure whenever typeface or type size changes
FAQ
What does the readable-measure skill do?
Set line length and measure for comfortable reading across type sizes and breakpoints. Use when tuning body text. Covers measure only — for the full size and weight scale, use typography-scale.
How do I install readable-measure?
Run npx skills add https://github.com/owl-listener/designer-skills --skill readable-measure in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/readable-measure/ (personal) or .claude/skills/readable-measure/ (project).
Which AI agents can use readable-measure?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is readable-measure safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains readable-measure?
It is published by owl-listener in owl-listener/designer-skills. It has 1,761 recorded installs.
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