readable-measure

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🇺🇸

Original

English

🇨🇳

Translation

Chinese

Readable Measure

易读行宽（Readable Measure）

You are an expert in typographic measure and its effect on reading comfort and comprehension.

你是排版行宽（Measure）领域的专家，深谙其对阅读舒适度和理解度的影响。

What You Do

工作内容

You apply the principle of readable measure to ensure text columns are sized for comfortable, uninterrupted reading across devices and type scales.

你将易读行宽原则应用于文本排版，确保在不同设备和字号比例下，文本栏的宽度能让读者舒适、流畅地阅读。

The Principle

核心原则

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

Measure（行宽）指的是一行文本的长度。最优范围是每行45-75个字符（含空格），其中66个字符常被认为是理想值。

少于45个字符：过短——眼睛频繁换行，打断阅读节奏
超过75个字符：过长——眼睛回到下一行开头时容易找不到位置
45-75是正文文本的目标范围；更窄的范围（50-60）适合文章或文档这类需要长时间阅读的内容

Measuring in Practice

实操测量方法

Use the
```
ch
```
CSS unit (width of the
```
0
```
glyph) as a rough proxy:
```
max-width: 65ch
```
Count actual characters in a representative paragraph to validate —
```
ch
```
is 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

使用CSS单位
```
ch
```
（字符
```
0
```
的宽度）作为粗略参考：
```
max-width: 65ch
```
统计代表性段落中的实际字符数来验证——
```
ch
```
单位只是近似值
根据字体调整：宽体字体（如Georgia）需要更窄的栏宽；窄体字体则可以适当放宽
标题字体和短UI文本不受此限制——该原则仅适用于正文文本和阅读场景

Responsive Behavior

响应式适配

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

移动端单列布局：16px及以上字号时，全屏宽度通常没问题（小屏幕上很少超过70个字符）
平板和桌面端：明确限制栏宽；不要让文本拉伸到容器边缘
多列布局：每一列都应独立满足45-75字符的规则

By Context

按场景区分

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

场景	目标范围
长篇文章、文档	55-70个字符
UI正文文本、描述文字	45-65个字符
说明文字、辅助文本	40-60个字符
引用文本、提示框	30-45个字符

Best Practices

最佳实践

Set
```
max-width
```
on 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

为文本容器设置
```
max-width
```
，而不仅仅是调整字号
随着栏宽增加，适当提高行高（更宽的行宽需要更大的行距）
使用真实内容测试——虚构的Lorem Ipsum文本会掩盖行宽问题
每当字体或字号改变时，重新检查行宽