The absolute unit of typography, standardized as 1/72 inch

Points measure font size, line spacing (leading), and other typographic dimensions. A 12pt font means the distance from the lowest descender to the highest ascender is 12 points (1/6 inch or 4.23mm). The point system provides device-independent measurements that translate consistently across media.

Example: 12pt Times New Roman = 0.1667 inches tall = 4.23mm. Professional body text typically uses 10-12pt, headlines 18-72pt.

The digital unit representing a single dot on a screen or image

Pixels are device-dependent units that vary based on screen density (DPI/PPI). The same pixel count appears larger on low-resolution displays (72 PPI) and smaller on high-resolution retina displays (220+ PPI). Understanding DPI/PPI relationships is crucial for consistent typography across devices.

Example: 16px at 96 DPI = 12pt. The same 16px at 300 DPI (print) = 3.84pt. Always specify target DPI when converting pixels.

Traditional typographic unit equal to 12 points or 1/6 inch

Picas measure column widths, margins, and page layout dimensions in traditional print design. Desktop publishing software like InDesign and QuarkXPress use picas as the default measurement unit. One pica equals exactly 12 points, making conversions straightforward.

Example: A standard newspaper column might be 15 picas wide (2.5 inches or 180 points). Magazine layouts often use 30-40 pica measures.

1450–1737

The birth of movable type created the need for standardized measurements, but regional systems remained incompatible for centuries.

• 1450: Gutenberg's printing press creates need for standardized type sizes
• 1500s: Type sizes named after Bible editions (Cicero, Augustin, etc.)
• 1600s: Each European region develops own point system
• 1690s: French typographer Fournier proposes 12-division system
• Early systems: Wildly inconsistent, differing by 0.01-0.02mm between regions

1737–1886

French printer François-Ambroise Didot created the first true standard, adopted across Continental Europe and still used in France and Germany today.

• 1737: Fournier proposes point system based on French royal inch
• 1770: François-Ambroise Didot refines system — 1 Didot point = 0.376mm
• 1785: Cicero (12 Didot points) becomes standard measure
• 1800s: Didot system dominates Continental European printing
• Modern: Still used in France, Germany, Belgium for traditional print

1886–1984

American and British printers standardized the pica system, defining 1 point as 0.013837 inches (1/72.27 inch), dominating English-language typography.

• 1886: American Type Founders establish pica system: 1 pt = 0.013837"
• 1898: British adopt American standard, creating Anglo-American unity
• 1930s-1970s: Pica system dominates all English-language printing
• Difference: Anglo-American point (0.351mm) vs Didot (0.376mm) — 7% larger
• Impact: Required separate type castings for US/UK vs European markets

1984–Present

Adobe's PostScript standard unified global typography by defining 1 point as exactly 1/72 inch, ending centuries of incompatibility and enabling digital typography.

• 1984: Adobe PostScript defines 1 pt = 1/72 inch exactly (0.3528mm)
• 1985: Apple LaserWriter makes PostScript standard for desktop publishing
• 1990s: PostScript point becomes global standard, replacing regional systems
• 2000s: TrueType, OpenType adopt PostScript measurements
• Modern: PostScript point is universal standard for all digital design

Established 1770 by François-Ambroise Didot

The Continental European standard, still used in France, Germany, and parts of Eastern Europe for traditional printing.

• 1 Didot point = 0.376mm (vs PostScript 0.353mm) — 6.5% larger
• 1 Cicero = 12 Didot points = 4.51mm (comparable to pica)
• Based on French royal inch (27.07mm), providing metric-like simplicity
• Still preferred in European art book and classical printing
• Modern use: French Imprimerie nationale, German Fraktur typography

Created 1978 by Donald Knuth for computer typesetting

The academic standard for mathematical and scientific publishing, optimized for precise digital composition.

• 1 TeX point = 1/72.27 inch = 0.351mm (matches old Anglo-American point)
• Chosen to preserve compatibility with pre-digital academic publications
• 1 TeX pica = 12 TeX points (slightly smaller than PostScript pica)
• Used by LaTeX, the dominant scientific publishing system
• Critical for: Academic papers, mathematical texts, physics journals

Microsoft Word and Windows typography

The internal measurement unit for word processors, providing fine-grained control for digital document layout.

• 1 twip = 1/20 point = 1/1440 inch = 0.0176mm
• Name: 'TWentieth of a Point' — extremely precise measurement
• Used internally by: Microsoft Word, Excel, PowerPoint, Windows GDI
• Allows fractional point sizes without floating-point math
• 20 twips = 1 point, enabling 0.05pt precision for professional typesetting

1886 American Type Founders standard

The pre-digital standard for English-language printing, slightly different from PostScript.

• 1 printer's point = 0.013837 inch = 0.351mm
• Equals 1/72.27 inch (vs PostScript 1/72) — 0.4% smaller
• Pica = 0.166 inch (vs PostScript 0.16667) — barely perceptible difference
• Dominated 1886-1984 before PostScript unification
• Legacy impact: Some traditional print shops still reference this system

The word 'font' comes from French 'fonte' meaning 'cast' or 'melted'—referring to the molten metal poured into molds to create individual metal type pieces in traditional letterpress printing.

PostScript chose 72 points per inch because 72 is divisible by 2, 3, 4, 6, 8, 9, 12, 18, 24, and 36—making calculations easier. It also closely matched the traditional pica system (72.27 points/inch).

Bauer Bodoni costs $89,900 for the complete family—one of the most expensive commercial fonts ever sold. Its design required years of work to digitize from original 1920s metal type specimens.

Despite designer hatred, Comic Sans increases reading speed for dyslexic readers by 10-15% due to irregular letter shapes that prevent character confusion. It's actually a valuable accessibility tool.

The '@' symbol has different names in different languages: 'snail' (Italian), 'monkey tail' (Dutch), 'little mouse' (Chinese), and 'rolled pickled herring' (Czech)—but it's the same 24pt character.

Apple chose 72 DPI for original Macs to match PostScript points exactly (1 pixel = 1 point), making WYSIWYG desktop publishing possible for the first time in 1984. This revolutionized graphic design.

Gutenberg invents movable type—first need for type measurement standards

François-Ambroise Didot creates Didot point system (0.376mm)

American Type Founders standardize pica system (1 pt = 1/72.27 inch)

Donald Knuth creates TeX point system for academic typesetting

Adobe PostScript defines 1 pt = 1/72 inch exactly—global unification

Apple LaserWriter brings PostScript to desktop publishing

TrueType font format standardizes digital typography

CSS introduces web typography with pixel-based measurements

iPhone introduces @2x retina displays—density-independent design

Android launches with dp (density-independent pixels)

Web fonts (WOFF) enable custom typography online

Variable fonts specification—single file, infinite styles

96 DPI (96 pixels per inch)

Microsoft standardized on 96 DPI in Windows 95, creating a 4:3 ratio between pixels and points. This remains the default for most PC displays.

• 1 px at 96 DPI = 0.75 pt (4 pixels = 3 points)
• 16px = 12pt — common body text size conversion
• History: Chosen as 1.5× the original 64 DPI CGA standard
• Modern: High-DPI displays use 125%, 150%, 200% scaling (120, 144, 192 DPI)
• Web default: CSS assumes 96 DPI for all px-to-physical conversions

72 DPI (legacy), 220 PPI (@2x Retina)

Apple's original 72 DPI matched PostScript points 1:1. Modern Retina displays use @2x/@3x scaling for crisp rendering.

• Legacy: 1 px at 72 DPI = 1 pt exactly (perfect correspondence)
• Retina @2x: 2 physical pixels per point, 220 PPI effective
• Retina @3x: 3 physical pixels per point, 330 PPI (iPhone)
• Advantage: Point sizes match across screen and print preview
• Reality: Physical Retina is 220 PPI but scaled to appear as 110 PPI (2×)

160 DPI (density-independent pixel)

Android's dp (density-independent pixel) system normalizes to 160 DPI baseline, with density buckets for different screens.

• 1 dp at 160 DPI = 0.45 pt (160 pixels/inch ÷ 72 points/inch)
• Density buckets: ldpi (120), mdpi (160), hdpi (240), xhdpi (320), xxhdpi (480)
• Formula: physical pixels = dp × (screen DPI / 160)
• 16sp (scale-independent pixel) = recommended minimum text size
• Advantage: Same dp value appears physically identical across all Android devices

72 DPI (@1x), 144 DPI (@2x), 216 DPI (@3x)

iOS uses point as a logical unit identical to PostScript points, with physical pixel counts depending on screen generation (non-retina @1x, retina @2x, super-retina @3x).

• 1 iOS point at @1x = 1.0 pt PostScript (72 DPI baseline, same as PostScript)
• Retina @2x: 2 physical pixels per iOS point (144 DPI)
• Super Retina @3x: 3 physical pixels per iOS point (216 DPI)
• All iOS designs use points; system handles pixel density automatically
• 17pt = minimum recommended body text size (accessibility)

Printer resolution — how many ink dots fit in one inch

DPI measures printer output resolution. Higher DPI produces smoother text and images by placing more ink dots per inch.

• 300 DPI: Standard for professional printing (magazines, books)
• 600 DPI: High-quality laser printing (business documents)
• 1200-2400 DPI: Professional photo printing and fine art reproduction
• 72 DPI: Screen preview only — unacceptable for print (looks jagged)
• 150 DPI: Draft printing or large-format posters (viewed from distance)

Screen resolution — how many pixels fit in one inch of display

PPI measures display density. Higher PPI creates sharper screen text by packing more pixels into the same physical space.

• 72 PPI: Original Mac displays (1 pixel = 1 point)
• 96 PPI: Standard Windows displays (1.33 pixels per point)
• 110-120 PPI: Budget laptop/desktop monitors
• 220 PPI: MacBook Retina, iPad Pro (2× pixel density)
• 326-458 PPI: iPhone Retina/Super Retina (3× pixel density)
• 400-600 PPI: High-end Android phones (Samsung, Google Pixel)

Print uses absolute units (points, picas) because physical output size must be exact and device-independent.

• Body text: 10-12pt for books, 9-11pt for magazines
• Headlines: 18-72pt depending on hierarchy and format
• Leading (line spacing): 120% of font size (12pt text = 14.4pt leading)
• Measure absolute dimensions in picas: 'Column width: 25 picas'
• Always design at 300 DPI for professional printing
• Never use pixels for print — convert to points/picas/inches

Web typography uses pixels and relative units because screens vary in size and density.

• Body text: 16px default (browser standard) = 12pt at 96 DPI
• Never use absolute points in CSS — browsers render unpredictably
• Responsive design: Use rem (relative to root font) for scalability
• Minimum text: 14px for body, 12px for captions (accessibility)
• Line height: 1.5 (unitless) for body text readability
• Media queries: Design for 320px (mobile) to 1920px+ (desktop)

Mobile platforms use density-independent units (dp/pt) to ensure consistent physical size across different screen densities.

• iOS: Design in points (pt), system scales to @2x/@3x automatically
• Android: Use dp (density-independent pixels) for layouts, sp for text
• Minimum touch target: 44pt (iOS) or 48dp (Android) for accessibility
• Body text: 16sp (Android) or 17pt (iOS) minimum
• Never use physical pixels — always use logical units (dp/pt)
• Test on multiple densities: mdpi, hdpi, xhdpi, xxhdpi, xxxhdpi

Academic publishing uses TeX points for mathematical precision and compatibility with established literature.

• LaTeX uses TeX points (72.27 per inch) for legacy compatibility
• Standard journal: 10pt Computer Modern font
• Two-column format: 3.33 inch (240pt) columns with 0.25 inch (18pt) gutter
• Equations: Precise point sizing critical for mathematical notation
• Convert carefully: 1 TeX pt = 0.9963 PostScript pt
• PDF output: TeX automatically handles point system conversions

• Always work in points or picas — never pixels for print
• Set up documents at actual size (300 DPI) from the start
• Use 10-12pt for body text; anything smaller reduces readability
• Leading should be 120-145% of font size for comfortable reading
• Margins: Minimum 0.5 inch (36pt) for binding and handling
• Test print at actual size before sending to commercial printer

• Use rem for font sizes — enables user zoom without breaking layout
• Set root font to 16px (browser default) — never smaller
• Use unitless line-height values (1.5) rather than fixed heights
• Never use absolute point sizes in CSS — unpredictable rendering
• Test on actual devices, not just browser resize — DPI matters
• Min font size: 14px body, 12px captions, 44px touch targets

• iOS: Design @1x, export @2x and @3x assets automatically
• Android: Design in dp, test on mdpi/hdpi/xhdpi/xxhdpi
• Minimum text: 17pt (iOS) or 16sp (Android) for accessibility
• Touch targets: 44pt (iOS) or 48dp (Android) minimum
• Test on physical devices — simulators don't show true density
• Use system fonts when possible — optimized for platform

• Minimum body text: 16px (web), 17pt (iOS), 16sp (Android)
• High contrast: 4.5:1 for body text, 3:1 for large text (18pt+)
• Support user scaling: Use relative units, not fixed sizes
• Line length: 45-75 characters per line for optimal readability
• Line height: 1.5× font size minimum for dyslexia accessibility
• Test with screen readers and zoom at 200%

Photoshop assumes 72 PPI for screen display, while Word uses 96 DPI (Windows) for layout. A 12pt font in Photoshop appears 33% larger on screen than in Word, even though both print at identical sizes. Set Photoshop to 300 PPI for print work to see accurate sizing.

Always pixels (or relative units like rem/em) for web. Points are absolute physical units that render inconsistently across browsers and devices. 12pt might be 16px on one device and 20px on another. Use px/rem for predictable web typography.

pt = absolute physical (1/72 inch), px = screen pixel (varies with DPI), dp = Android density-independent (normalized to 160 DPI). Use pt for print, px for web, dp for Android, iOS pt (logical) for iOS. Each system optimizes for its platform.

Applications interpret points differently based on their DPI assumption. Word uses 96 DPI, Photoshop defaults to 72 PPI, InDesign uses actual device resolution. 12pt is always 1/6 inch when printed, but appears different sizes on screen due to DPI settings.

Multiply TeX points by 0.9963 to get PostScript points (1 TeX pt = 1/72.27 inch vs PostScript 1/72 inch). The difference is tiny—only 0.37% —but matters for academic publishing where exact spacing is critical for mathematical notation.

Print: 300 DPI minimum, 600 DPI for high-quality. Web: Design at 96 DPI, provide @2x assets for retina. Mobile: Design @1x in logical units (pt/dp), export @2x/@3x. Never design at 72 DPI unless targeting legacy Mac displays.

Browser default font size is 16px (equivalent to 12pt at 96 DPI), chosen for optimal readability at typical viewing distances (18-24 inches). Anything smaller reduces readability, especially for older users. Always use 16px as your base for relative sizing.

Only if working with European traditional printing, French publishers, or historical reproductions. Didot points (0.376mm) are 6.5% larger than PostScript points. Modern digital design universally uses PostScript points—Didot is mainly relevant for classical typography and art books.