Pixel Five is a free, open source, monospaced font, designed to be the smallest legible. It has a character area of five square pixels. It was last updated on 2021-09-14 as version 1.013.
Pixel Five is designed to be the smallest legible monospaced, aliased font.
Its native display size is 5pt at 72ppi (PostScript/Mac) or 3.75pt at 96ppi (Windows), resulting of a character area of five square pixels (or six, including letter and line spacing).
The font covers the full basic and extended ASCII character sets for Windows Latin and Mac Roman, and contains several additional portions of Unicode.
For pixel-perfect display, the ideal size is 5 points at 72 points per inch (or 3.75 points at 96 points per inch).
Notes
Pixel Five is meant to help display legible, monospaced text within the minimum possible space. It may be useful for low-resolution displays and retro typographic design.
What is the smallest possible font?
Without regard to antialiasing (especially that of the subpixel variety).
A 5x5 pixel area was discovered to be the minimum for a reasonably legible English/Latin font without anti-aliasing.
Smaller fonts are of course possible, though characters become chunky and muddled, and more difficult to distinguish from one another. Particularly uppercase vs. lowercase letters, and several symbols.
In terms of only representing uppercase letters, the smallest legible and distinct monospaced size is 3x2. Though 3x3 and 3x4 offer much better readability. Obviously with variable spacing, minimums are reduced per-character; the letter I only requires one pixel of width, for example.
As the available area decreases, so does legibility. Representing more characters that are distinguishable from each other requires more possible unique arrangements of dots.
So while we may say legibility is not significantly impacted with regards to a certain character subset, the number of characters we can represent decreases and eventually this decrease reaches the minimum number of alphabetic characters we may consider for practical use as a font.
1x1 Pixels
If we consider a font as allowing one-to-one representation of a character alphabet, then we cannot consider the technically smallest font size of 1x1 pixel. Since while this could be used as a way of representing binary-encoded data manually, it could not be used practically by the general definition of a font. And though such fonts may have programmatic use, it would be far simpler (and usually faster) to use direct bitmap graphics to render a string of arbitrary black dots.
Pixel Five is open source under an MIT-style license, free for any use. If you create variations, I'd love to see what you do with it, and include any improvements in mine, if you'd allow it.
Character Set
Basic ASCII
NULSOHSTXETXEOTENQACKBELBSTABLFVTFFCRSOSIDLEDC1DC2DC3DC4NAKSYNETBCANEMSUBESCFSGSRSUS
SPC!"#$%&'()*+,-./0123456789:;<=>?
@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_
`abcdefghijklmnopqrstuvwxyz{|}~DEL
Extended ASCII
€ ‚ƒ„…†‡ˆ‰Š‹Œ Ž ‘’“”•–—˜™š›œ žŸ
NBSP¡¢£¤¥¦§¨©ª«¬SHY®¯°±²³´µ¶·¸¹º»¼½¾¿
ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞß
àáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ
(Plus various Unicode)
Specifications
Family: Pixel Five
Style: Regular
PostScript Name: PixelFive-Regular
Unique Name: 1.013;UKWN;PixelFive-Regular
Format: OpenType (PostScript Flavored)
Designer: Adam Bjornson
Designer URL: http://www.adambjornson.com/
Vendor: None
Copyright: Adam Bjornson
License: MIT-style
Embedding Rights: Preview & Print Embedding Allowed
Version: 1.013
Version Date: 2021-09-14
File Name: Pixel Five.otf
File Format: OpenType font
File Size: 29,600 bytes
Weight: Regular
Width: Regular / Medium (Normal)
Units Per Em: 1000
Character Width: -
Ascender: 1000
Cap Height: 800
x-Height: 600
Descender: 0
Vertical Stems: 0
Horizontal Stems: 0
Grid Spacing: 200
Subdivision: 1
Italic Angle: 0
Monospaced: True
Generator: Glyphs Mini 1.5.3
Engine: PS 001.075, hotconv 1.0.70, makeotf.lb 2.5.58329
Native Size: 5pt
Optimal Density: 72ppi
Line Width: 480px for 80 characters at 5pt
Compare With: 480px for Monaco, Courier at 8pt
Line Height: 6px at 12pt
Compare With: 6px for Monaco, Courier at 6pt
Languages: Latinesque, Romanesque
Glyphs: 457
Glyph Set: (see above)
ASCII Coverage: 100% (128/128)
Extended ASCII Coverage (Windows-1252): 100% (128/128)
Additional Unicode Glyphs: 243
