Free Online LaTeX Equation Editor

What This LaTeX Equation Editor Does

Searches for an online LaTeX editor split into 2 very different needs. One group wants a document environment: chapters, cross-references, a bibliography that renumbers itself and a PDF at the end. The other group has one expression stuck in their head and a slide due in an hour.

This tool serves the second group.

The distinction is not pedantic. A document compiler has to resolve packages, run several passes over the file and reconcile every reference before it can show you anything. An equation renderer only has to typeset a short expression, which KaTeX does in a few milliseconds without ever contacting a server. Different problem, different machine.

So the trade is deliberate. You give up documents. You get speed.

If your work sits on the wrong side of that table, this is the wrong page. The roundup of online LaTeX editors that run in a browser covers the document environments, and the guide to desktop LaTeX editors for Windows and Mac covers local installs.

How to Write LaTeX Equations

Almost everything in school and undergraduate math comes down to 4 constructions. Learn these and the symbol palette above handles the rest.

• x^2 raises to a power.
• x_i drops to a subscript.
• \frac{a}{b} stacks a fraction, numerator first and denominator second.
• \sqrt{x} takes a square root, and \sqrt[3]{x} takes a cube root.

The rule that trips up almost everyone is grouping. A superscript or subscript applies to exactly 1 character unless you wrap the rest in braces.

x^10 renders as x to the power 1, followed by a stray 0.

x^{10} renders as x to the power 10.

That single pair of braces is the difference between a correct formula and a formula that looks right to you and wrong to whoever is marking it.

Greek letters follow their names, so \alpha gives you the letter and \beta gives you the next one. Capitalize the command for the capital letter: \pi is the small one, \Pi is the product sign. Function names take a backslash too, because \sin x sets sin upright the way mathematical typography expects, while sin x sets it in italics, as though s, i and n were 3 variables being multiplied.

Small thing. Very visible.

The chapter on math modes, fractions and symbols goes deeper on spacing and delimiters, and the symbol quick reference is the page to keep open during an exam week.

Four Equations Worth Copying

I have kept these 4 deliberately plain, because the structure is the lesson and not the mathematics. Each renders in the editor above with no setup. Paste one in, then change the letters to match your problem.

Quadratic Formula

x = \frac{-b \pm \sqrt{b^2-4ac}}{2a}

This one is worth reading closely because it nests. The \sqrt sits inside the numerator argument of \frac, and \pm produces the plus-or-minus sign that would otherwise take 2 separate equations to express. Once you can read this expression, you can read most of a first-year textbook.

Definite Integral

\int_{0}^{1} x^2\,dx = \frac{1}{3}

The limits attach to \int as a subscript and a superscript, exactly like they do on any other symbol. The \, is a thin space, and it is the difference between x²dx crammed together and the spacing a journal would print.

Matrix

\begin{pmatrix}
a & b \\
c & d
\end{pmatrix}

Ampersands separate columns and a double backslash ends a row. Swap pmatrix for bmatrix to get square brackets, or vmatrix to get the vertical bars of a determinant. The structure stays identical, which is why multi-line equations and matrices are easier than they look.

Piecewise Function

f(x) =
\begin{cases}
x^2, & x \geq 0 \\
-x, & x < 0
\end{cases}

The cases environment draws the large brace and aligns both the expressions and the conditions. Writing this by hand in a word processor usually means a text box, a manually drawn bracket and a lifetime of nudging.

Export Formats and Output Sizes

Output size is a pixel multiplier, not a DPI setting. That distinction matters because the wrong mental model here produces blurry slides.

• 1x exports the equation at roughly the size it appears on screen.
• 2x doubles the width and the height, so the file holds 4 times as many pixels.
• 3x and 4x scale the same way, 9 times and 16 times the pixel count.

The editor prints the exact dimensions after every export, so nothing has to be guessed. E = mc^2 with 20px of padding comes out 147 by 67 pixels at 1x and 587 by 267 pixels at 4x.

DPI belongs to the destination, not to the file. That same 587 pixel wide export is about 8 inches across in a 72 DPI web layout and just under 2 inches across in a 300 DPI print job. Pick the multiplier by asking how large the equation will physically appear, not by chasing a number.

What most people export:

A 2x PNG, into everything.

What works better where the destination allows it:

An SVG.

Same equation. The SVG stores every letterform as an outline instead of a grid of pixels, so it stays crisp when a slide gets projected onto a wall or a page goes to a 600 DPI printer, and it opens as editable vector art in Illustrator, Inkscape or Affinity Designer. PNG is the safer choice when you do not control the software on the other end.

Transparent is the background to pick whenever the equation is going on top of anything that is not white. It exports with genuine alpha, not a white rectangle pretending to be invisible.

What KaTeX Renders, and What It Doesn’t

KaTeX implements a defined list of TeX commands and environments. It is a typesetter, not a compiler: it knows how to draw the symbols, and it was never taught how to build a book. Nothing on this page loads a LaTeX package.

It renders:

• fractions, roots, superscripts and subscripts
• sums, products, integrals, contour integrals and limits
• matrices through pmatrix, bmatrix, vmatrix and friends
• piecewise definitions through cases
• multi-line alignment through align and aligned
• Greek letters, accents, arrows, set notation and logic notation
• font switches such as \mathbb, \mathcal and \mathfrak

It does not render:

• TikZ or pgfplots diagrams
• \usepackage and arbitrary package macros
• document classes, sections, floats or captions
• bibliographies and citations
• \includegraphics and external files

The official KaTeX support table is the authority when you are unsure about a specific command, and the chapter comparing KaTeX and MathJax explains why a site would choose one over the other.

Common Errors and What They Mean

The editor stops and tells you where the problem is rather than rendering something wrong. The messages are precise once you know what they are pointing at.

• Unexpected end of input in a macro argument means a brace never closed. Count your { against your }.
• Undefined control sequence means the command does not exist in KaTeX. Usually a typo, sometimes a package command that was never going to work here.
• Too many expansions means a macro is defining itself in a loop. The renderer stops rather than freezing the tab.
• Expected ‘EOF’, got ‘&’ means an alignment character is sitting outside a matrix, cases or aligned environment.
• Double superscript means two ^ marks apply to the same base. Group the exponent: x^{2^n}, not x^2^n.

The reference on the most common LaTeX errors covers the ones that only show up in full documents, which is where the confusing ones live.

Getting Equations Into Word, Docs and Notion

Before exporting an image, check whether the destination reads LaTeX itself. Several do, and a native equation beats a picture of one every time: it stays editable, it is searchable, it reflows with the text and a screen reader can read it aloud.

Microsoft Word has accepted LaTeX input for years.

1. Copy the LaTeX source from the editor above.
2. Press Alt and = together to open an equation field.
3. On the Equation tab, set the input format to LaTeX.
4. Paste the expression.
5. Choose Professional to typeset it.

Notion is the other easy one, because its equation blocks are rendered by KaTeX. Whatever renders in the preview above will render there, so paste the source rather than the image. Google Docs converts a subset of LaTeX-style commands inside its own equation field, which covers fractions and Greek letters but stops well short of matrices.

The image export earns its place where the destination cannot do better: Google Slides and PowerPoint, video editors, forum posts, learning platforms that strip markup, and anywhere the equation is a picture and nothing more. The chapter on writing math in everyday tools works through each of those destinations properly.

The Limits

I would rather you know these before building a workflow on top of the editor.

• It renders one expression at a time. There is no document, no equation numbering and no cross-referencing.
• Rendering happens after the page and its assets have loaded. An open tab keeps working if your connection drops, but the page will not reopen offline, because nothing is cached for that.
• Recent equations live in this browser’s local storage. A different browser, a different device or a private window all start with an empty list, and clearing site data deletes them.
• Exports are drawn by a separate rendering engine so the file carries real vector outlines. That engine downloads on your first export, which makes the first PNG or SVG take a moment longer than every one after it.
• Very large sizing commands are capped, so a deliberately enormous \rule will not render at its requested size.

For anything with chapters, a bibliography or a supervisor’s template, a full TeX installation is still the answer, and LaTeX for Students covers that route from zero.

What Quietly Ruins an Exported Equation

None of these throw an error. They just make the result look amateurish in a way that is hard to diagnose after the fact.

Exporting at 1x because the preview looked fine. The preview is sized for your screen, and a 1x PNG blown up to fill a projected slide turns into a soft grey smudge. 2x is a sensible floor for anything that will be enlarged.

Leaving the background white on a dark slide. The equation arrives inside a bright rectangle that announces itself as a pasted image from the back of the room. Transparent, with the equation color set to something light, fixes it in 2 clicks.

Cropping the padding off the exported file afterwards. That padding is protecting the parts of the expression that reach outside the main line: the tail of an integral sign, the descender on a subscript, the top of a square root. Crop tight and you clip them.

Screenshotting the preview instead of exporting. A screenshot captures at whatever your display happens to be, picks up the preview background and cannot be scaled up later. The export exists precisely to avoid that.

Using an image where the destination reads LaTeX. Word, Notion and most static site generators will typeset the expression themselves, and every one of those versions is more accessible and easier to correct than a picture.

FAQs on the LaTeX Equation Editor

The questions that come up most often about writing and exporting equations here.

Final Remarks

The gap between knowing the math and having the math sit correctly in your document is mostly a tooling problem, and it is smaller than the internet makes it look. The usual advice sends a student to install a full TeX distribution, and an afternoon later they have a working compiler and one fraction to show for it.

One expression at a time is a smaller ambition. It is also the one that gets the slide finished.

Write the expression, check the preview, export at 2x, and get back to the actual work.