Point

Formal Definition

The point (symbol: pt) is a unit of measurement used in typography to specify the size of type, leading (line spacing), and other typographic elements. In the modern desktop publishing (DTP) standard — established by Adobe PostScript and adopted by CSS — one point is defined as exactly 1/72 of an inch, or approximately 0.3528 mm. This definition, sometimes called the PostScript point or DTP point, has become the universal standard in digital typography.

The point is the smallest commonly used unit in typography. Twelve points equal one pica, and six picas (72 points) equal one inch. In CSS, one point equals 1.333 pixels at the standard 96-PPI reference resolution. Font sizes, line heights, paragraph spacing, and many other typographic measurements are traditionally expressed in points.

Historical Variants

Before the PostScript point became dominant, several slightly different point systems existed. The Didot point (used in continental Europe) equals approximately 0.376 mm, making it about 6.6% larger than the DTP point. The American Printer's point (also called the Pica point) was defined as 0.01383 inches (approximately 0.3514 mm), which is very close to but not identical with the DTP point. The PostScript definition of exactly 1/72 inch simplified calculations and became the global standard with the rise of desktop publishing in the mid-1980s.

Origin of the Term

The word "point" in the typographic sense derives from the French "point," meaning a dot, mark, or small unit. In typography, it originally referred to the smallest practical unit of measurement. The French word comes from the Latin "punctum" (a pricking, a point), from "pungere" (to prick or pierce) — the same root that gives us "punctuate," "puncture," and "punctual."

Typographic Context

The point system was developed to bring standardization to an industry that had previously specified type sizes by name rather than by numerical measurement. Before the point system, type sizes bore names like "nonpareil" (approximately 6 points), "brevier" (8 points), "long primer" (10 points), and "pica" (12 points). These names varied between countries and even between type foundries, making precise specification difficult. The point system replaced this confusion with a numerical framework that could be universally understood.

Pierre-Simon Fournier

The typographic point system was first proposed by Pierre-Simon Fournier le Jeune, a French typographer and type founder, in 1737. Fournier divided the cicero (a standard type body used in French printing) into 12 parts, which he called "points." His system was published in his "Table des Proportions" and later expanded in his influential work "Manuel Typographique" (1764-1766). Fournier's point was approximately 0.349 mm.

Francois-Ambroise Didot

In the 1780s, Francois-Ambroise Didot refined Fournier's system by basing the point on the French royal inch ("pied de roi"). Didot's point equaled 1/72 of the French inch, which was approximately 0.376 mm — slightly larger than Fournier's point. The Didot system became the standard in continental Europe and remained in use in many European countries well into the 20th century. In Germany, the Didot point was officially adopted by the Typographic Society of Leipzig in 1879.

The American Point System

In the United States, a different point system developed. In 1878, the Chicago Type Foundry proposed a system based on the pica (a common type body). In 1886, the United States Typefounders Association officially adopted the "American Point" of 0.01383 inches (approximately 1/72.27 inch or 0.3514 mm). This system spread to Britain and became the standard in English-speaking countries throughout the 20th century.

The PostScript Revolution

In 1984, Adobe Systems defined the PostScript point as exactly 1/72 of an inch (0.3528 mm) for its PostScript page description language. This simplified the relationship between points and inches to a clean fraction and eliminated the tiny discrepancy in the American point system. When Apple's LaserWriter printer brought PostScript to the desktop in 1985, the PostScript point rapidly became the de facto standard. By the 1990s, virtually all desktop publishing software — including Adobe InDesign, QuarkXPress, and Microsoft Word — used the PostScript point definition.

In Desktop Publishing and Design

The point is the standard unit for font size in virtually all design and publishing software. Body text in books and documents is typically set at 10 to 12 points. Newspaper body text is often 9 to 10 points. Headlines range from 18 to 72 points or larger. Leading (line spacing) is usually specified as the font size plus 2 to 4 points — for example, 12-point type on 15-point leading (written as 12/15). Paragraph spacing, indentation, and rule weights are also commonly specified in points.

In CSS and Web Design

CSS supports points as a length unit (pt), and they are occasionally used in stylesheets intended for print output. However, pixels (px) and relative units (em, rem) are preferred for screen design. When generating PDFs or defining print stylesheets, points remain the standard unit. CSS defines 1 pt = 1/72 in = 1.333 px at 96 DPI.

In Word Processing

Every word processor — Microsoft Word, Google Docs, LibreOffice Writer — uses points as the unit for font size. Users select font sizes from dropdown menus showing values in points (8, 9, 10, 11, 12, 14, 16, 18, 20, 24, 28, 32, 36, 48, 72). This convention is so deeply ingrained that most people recognize "12-point font" as a standard document size without knowing the precise physical measurement.

Document Creation

Whenever someone creates a document — a letter, resume, report, or presentation — they interact with points. The most common instruction in office environments is to "use 12-point Times New Roman" or "11-point Calibri." Academic style guides (APA, MLA, Chicago) specify font sizes in points. Legal documents often require specific point sizes for readability. Business cards, letterheads, and marketing materials are all designed with type sizes specified in points.

Reading and Accessibility

Font size in points directly affects readability. The Americans with Disabilities Act and similar legislation in other countries often references minimum type sizes in points for signage and documents. Large-print books are typically set in 16 to 18 points. Prescription drug labels in the United States must use a minimum of 6-point type. Accessibility guidelines for web content recommend body text equivalent to at least 12 points.

Printing and Publishing

The entire publishing industry — books, magazines, newspapers, packaging — specifies type in points. A standard paperback novel uses 10 to 12-point text. Magazine body text is typically 9 to 11 points. Footnotes and captions are usually 7 to 9 points. The choice of point size, combined with typeface and leading, determines how many words fit on a page and how comfortable the text is to read.

In Typography Research

Typography researchers study the effects of point size on reading speed, comprehension, and eye fatigue. Studies have shown that for continuous reading, point sizes between 10 and 14 are optimal for adults, with 12 points being the most universally comfortable. Research on aging and vision impairment has established that readers over 65 benefit significantly from text set at 14 points or larger.

In Vision Science

Ophthalmic testing uses point-based size specifications. The Jaeger chart, used to test near visual acuity, defines text sizes in printer's points (J1 through J21+). Snellen chart equivalents are sometimes expressed in point sizes for near-vision testing. The minimum readable point size is a useful clinical measure of visual function.

In Information Design

Research in information design uses points as the standard measure for evaluating the legibility of maps, charts, labels, and signage. Edward Tufte's influential works on data visualization specify type sizes in points. The U.S. Department of Transportation specifies minimum letter heights for highway signs in inches but converts these to equivalent point sizes for printed materials.