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Short answer: in LaTeX math mode, type < for less than, \leq (or its synonym \le) for less than or equal to, and \ll for much less than. This guide is for researchers and analysts typesetting inequalities in papers, theses and reports, and it shows which symbol to use and why the spacing differs between them.
What it is used for in research
Inequalities appear in statistical thresholds (p < 0.05), bounds in proofs, constraints in optimisation and order-of-magnitude comparisons. LaTeX treats these symbols as different classes, which controls the space around them, so the choice of command is a typesetting decision as well as a meaning decision.
Install or access (official source only)
The commands below belong to core LaTeX math mode, so a standard TeX distribution compiles them. TeX Live and MiKTeX both contain the amsmath package (version 2.17z, dated 2025-07-09, listed on its CTAN page, read 2026-11-07), which you load with \usepackage{amsmath} for display environments and extra symbols. The symbol \vartriangleleft discussed below needs amssymb according to the LaTeX2e unofficial reference manual. Overleaf, a browser editor, documents the same symbols in its list of Greek letters and math symbols. For the equation-rendering side on the web, see MathJax and LaTeX.
Step-by-step: typing less-than symbols
- Enter math mode: put the expression between
$ ... $for inline math, for example$x < y$. - For strict less than, type the plain character
<. Overleaf’s Mathematical expressions page lists it in its “Relation operators” row alongside>,\subset,\supset,\subseteqand\supseteq. - For less than or equal to, type
\leq, for example$x \leq y$. The reference manual states that\leqis a synonym for\le. The mirror image is\geq. - For much less than, type
\ll; its counterpart is\gg. - Compile and check that each symbol renders as a relation with equal space on both sides.
Output and how to read it
| You want | Type | Class in the reference |
|---|---|---|
| Less than | < |
Relation operator (Overleaf, Mathematical expressions) |
| Less than or equal to | \leq or \le |
Relation |
| Much less than | \ll |
Relation |
| Much greater than | \gg |
Relation |
| Triangle shape | \triangle |
Ordinary symbol |
| Triangle used as a relation (normal subgroup) | \vartriangleleft with amssymb |
Relation |
The class matters because relations get relation spacing and ordinary symbols do not. That is why a triangle used as a relation should be \vartriangleleft, not \triangle, and why writing the two characters << is not the same as \ll.
How to get the less than or equal to symbol in LaTeX?
Use \leq or \le inside math mode. Typing <= produces a less-than sign followed by an equals sign, not a single symbol.
How do I write the triangle symbol in LaTeX?
Use \triangle for a plain triangle (an ordinary symbol, listed under miscellaneous symbols by Overleaf). If you need a triangle that acts as a relation between two terms, such as the normal subgroup symbol, load amssymb and use \vartriangleleft.
How to do << in LaTeX?
Use \ll for “much less than” (and \gg for “much greater than”). It is a single relation symbol with correct spacing.
What is the opposite of ≥?
The negation of “greater than or equal to” is “less than”, written <. The mirrored symbol \leq means “less than or equal to” and is not the logical opposite. For greater than or equal to itself, type \geq.
Troubleshooting
- Symbol missing or “Undefined control sequence”: check the command is typed in math mode and that a needed package (
amssymbfor\vartriangleleft) is loaded in the preamble. - Two symbols instead of one:
<=and<<are not single symbols; replace them with\leqand\ll. - Uneven spacing around a triangle: you used the ordinary
\trianglewhere a relation was intended; switch to\vartriangleleft. - Negated forms: the AMS negated binary relations are catalogued in the Comprehensive LaTeX Symbol List (Table 56) on CTAN; look the symbol up there.
Other ways to compile and reference
| Option | What the sources say |
|---|---|
| TeX Live | Contains the amsmath package (CTAN, read 2026-11-07) |
| MiKTeX | Contains the amsmath package (CTAN, read 2026-11-07) |
| Overleaf | Online editor with a documented symbol list; see also Overleaf alternatives for collaborative LaTeX |
| MathJax | Renders LaTeX math on web pages; see MathJax and LaTeX |
Related typesetting guides: square roots in LaTeX, number lines in LaTeX and LaTeX bibliography styles.
FAQ
Is \le the same as \leq?
Yes. The LaTeX2e unofficial reference manual describes \leq as a synonym for \le.
Where is the full symbol list?
The Comprehensive LaTeX Symbol List on CTAN and Overleaf’s symbol list are the standard references.
Sources (official docs)
- Overleaf, List of Greek letters and math symbols (read 2026-11-07)
- Overleaf, Mathematical expressions (read 2026-11-07)
- LaTeX2e unofficial reference manual, Math symbols (read 2026-11-07)
- CTAN, amsmath (read 2026-11-07)
- CTAN, The Comprehensive LaTeX Symbol List
