Fraction Symbols Guide

Fractions are a fundamental part of mathematical and everyday writing, yet typing them on a computer has always been awkward. Unicode solves this by providing precomposed fraction characters — single code points that render as properly formatted fractions like 1/2 or 3/4 — alongside the fraction slash character that enables the creation of arbitrary fractions. This guide catalogs every Unicode fraction character, explains the difference between the fraction slash and the regular solidus, and provides practical guidance for using fractions in HTML, CSS, and programming.

The Problem with Typed Fractions

When you type 1/2 on a keyboard, you are actually typing three separate characters: the digit 1, the solidus (/), and the digit 2. This looks passable in monospaced text but renders poorly in proportional fonts — the digits are full-size, the slash is a regular solidus, and the result is clearly not a proper fraction.

Compare:

The Unicode precomposed fraction ½ is a single character that renders as a properly typeset fraction in any font that supports it. No markup, no font features, no special rendering — just one code point.

Precomposed Vulgar Fractions

Unicode defines precomposed fraction characters in two blocks. The term vulgar fraction refers to a common fraction written with a numerator above (or before) a denominator, as opposed to a decimal fraction.

Latin-1 Supplement Fractions

These three fractions were present in the original Latin-1 (ISO 8859-1) character set and have the broadest support:

Number Forms Block Fractions

The Number Forms block (U+2150-U+218F) contains additional precomposed fractions:

That gives us a total of 20 precomposed fraction characters in Unicode.

The Fraction Slash (U+2044)

Not every fraction has a precomposed form. For arbitrary fractions like 5/16 or 7/32, Unicode provides the FRACTION SLASH character:

The fraction slash differs from the regular solidus (/) in a critical way: it signals to the rendering engine that the digits before it should be treated as a numerator and the digits after it as a denominator. OpenType-capable fonts with the frac feature will automatically render 5⁄16 as a proper fraction.

Three Slashes Compared

In Python, you can test the difference:

import unicodedata

solidus = "/"
fraction_slash = "\u2044"
division_slash = "\u2215"

print(unicodedata.name(solidus))          # SOLIDUS
print(unicodedata.name(fraction_slash))   # FRACTION SLASH
print(unicodedata.name(division_slash))   # DIVISION SLASH

Building Custom Fractions with Superscripts and Subscripts

For fractions without precomposed forms, you can combine Unicode superscript digits, the fraction slash, and subscript digits:

5⁄16  =  superscript-5 + fraction-slash + subscript-1 + subscript-6

The relevant superscript and subscript characters:

So to compose the fraction 5/16 using pure Unicode:

# Building 5/16 as a Unicode fraction
fraction = "\u2075\u2044\u2081\u2086"
print(fraction)  # ⁵⁄₁₆

Using Fractions in HTML

HTML provides several approaches to displaying fractions:

Named HTML Entities

CSS font-variant-numeric

Modern CSS provides the font-variant-numeric property with a diagonal-fractions or stacked-fractions value that automatically renders digit-slash-digit sequences as proper fractions:

.fractions {
    font-variant-numeric: diagonal-fractions;
}

With this CSS, any text like 1/2 or 3/4 within an element with the .fractions class will render as a typographically correct fraction, provided the font supports the OpenType frac feature.

Fractions in Python

Python's unicodedata module can extract the numeric value of fraction characters:

import unicodedata

fractions = "¼½¾⅓⅔⅕⅖⅗⅘⅙⅚⅛⅜⅝⅞⅐⅑⅒"

for char in fractions:
    value = unicodedata.numeric(char)
    name = unicodedata.name(char)
    print(f"{char}  U+{ord(char):04X}  = {value:.6f}  {name}")

This outputs the actual numeric value associated with each fraction character, which can be useful for text processing and mathematical computation.

When to Use Which Approach

Accessibility Considerations

Screen readers handle precomposed fraction characters well. Most screen readers will announce ½ as "one half", ¾ as "three quarters", and ⅓ as "one third". This is a significant advantage over the alternative 1/2 (which might be read as "one slash two") or HTML <sup>1</sup>/<sub>2</sub> (which might be read as "superscript one slash subscript two").

For accessibility, precomposed Unicode fractions are the best option whenever the needed fraction exists in Unicode.

Summary

Unicode provides 20 precomposed vulgar fraction characters that cover the most common fractions used in everyday text. For arbitrary fractions, the fraction slash (U+2044) combined with superscript and subscript digits enables typographically correct rendering. On the web, the CSS font-variant-numeric: diagonal-fractions property provides automatic fraction formatting. Choosing the right approach depends on the medium — plain text, web, print, or code — but in all cases, Unicode fractions offer better readability, accessibility, and semantic correctness than improvised digit-slash-digit sequences.