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About Typography Unit Conversion
Typography uses specialized units for measuring font sizes, line spacing, and layout dimensions. These units evolved from traditional printing—where physical type was set by hand—and have adapted for digital design while maintaining some historical conventions. 理解する them is essential for graphic design, web development, desktop publishing, and maintaining visual consistency across media.
The most common unit is the point (pt), with exactly 72 points per inch in the PostScript standard that became universal. Digital design also uses pixels (px) for screen layout and relative units like em and rem for responsive typography that scales with user preferences. Converting between these helps maintain consistency across print and digital media—a 12-point body text in print corresponds to 16 pixels at standard resolution on web.
Our converter handles all standard typography units used in print and digital design workflows.
Common Typography Conversions
| 変換元 | 変換先 | 乗数 |
|---|---|---|
| pt | inch | 0.01389 (1/72) |
| inch | pt | 72 |
| pt | mm | 0.3528 |
| mm | pt | 2.835 |
| pica | pt | 12 |
| pt | pica | 0.0833 |
| pt | px (96 dpi) | 1.333 |
| px | pt | 0.75 |
| inch | pica | 6 |
Typography 単位リファレンス
Point (pt) – The traditional type size unit, now standardized at exactly 1/72 inch (≈ 0.353 mm) in the PostScript/DTP point system. Before digital standardization, different point systems existed (Didot, Fournier). The point remains the standard for print font sizes, leading, and precise typographic work. 12 pt is standard body text; 72 pt headlines are 1 inch tall.
Pica – A larger typographic unit equal to 12 points = 1/6 inch (≈ 4.23 mm). Used for line lengths, column widths, margins, and text block dimensions in professional publishing. Page layouts are often specified in picas: a typical column might be 20-25 picas wide. Six picas = 1 inch exactly.
Pixel (px) – The fundamental digital screen unit, though its physical size varies with display density. CSS defines a reference pixel at 96 dpi (1 px = 1/96 inch ≈ 0.26 mm), but high-DPI displays may render multiple physical pixels per CSS pixel. Web design primarily uses pixels for layout, though relative units are increasingly preferred for accessibility.
Em – A relative unit equal to the current element's font size. If font-size is 16px, 1em = 16px. Em units compound in nested elements, which can cause unexpected sizing. Useful for padding and margins that should scale proportionally with text. Named after the width of capital M in traditional typography.
Rem (root em) – Relative to the root HTML element's font size, typically 16px by browser default. Unlike em, rem doesn't compound—1.5rem always equals 24px (at default settings) regardless of nesting depth. The preferred relative unit for consistent, accessible responsive design. Users who adjust browser font size see proportional scaling.
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