PTBox

LaTeX Math Formula Editor & Renderer

Online LaTeX math editor powered by KaTeX. Live preview with inline / display modes, a built-in cheat sheet (fractions, sums, integrals, matrices, equation systems), and one-click copy as LaTeX source or Markdown ($$...$$). Renders locally — formulas are never uploaded.

Common formulas / symbols (click to insert)
84 chars
Export / Copy
Code formats
Download

Everything runs locally — neither the formula nor the exported files leave the browser. PNG is rendered at 3× pixel density for slides / docs. Word export is an HTML-flavored .doc with an embedded image, opens natively in Microsoft Word.

Usage

LaTeX math formulas rendered locally by KaTeX — roughly 10× faster than MathJax and works entirely offline.

Two render modes: display ($$…$$) puts the formula on its own line with larger script size; inline ($…$) flows with text. Click any item in the cheat sheet to insert it at the cursor.

Invalid LaTeX shows a precise error message. Valid LaTeX that KaTeX doesn't implement (like \\usepackage or TikZ macros) is ignored — KaTeX supports a math subset, not the full LaTeX typesetting engine.

Use cases

Academic writing

Preview formulas live before pasting into Word / Overleaf / a thesis draft.

Technical blog & Markdown docs

Embed formulas in Markdown as $$…$$ — copy ready-to-paste form in one click.

Lecture slides / handouts

Tune symbols and equations here, then screenshot or copy into your slides.

Learning LaTeX syntax

The cheat-sheet plus side-by-side preview builds intuition faster than reading a tutorial.

FAQ

KaTeX vs MathJax?

KaTeX is faster (~10× rendering speed) and lighter. MathJax supports more LaTeX packages. For everyday formulas KaTeX is plenty.

Why don't \usepackage / TikZ work?

KaTeX implements a math subset of LaTeX — no package manager, no TikZ graphics. For full LaTeX use Overleaf or local compilation.

How do I write matrices or equation systems?

Matrices: \begin{pmatrix}…\end{pmatrix} (or bmatrix / vmatrix). Systems: \begin{cases}…\end{cases}. Templates are in the cheat sheet.

Does it render Chinese / non-math text?

KaTeX is mainly for math notation. Plain Chinese inside a formula renders fine, but don't use LaTeX as a general typesetter.

Can I export PNG or SVG?

Yes. PNG is rendered at 3× pixel density (great for slides); SVG is vector-lossless (great for print or scaling). A .doc file is also downloadable and opens natively in Word.

How do I get the formula into Word?

Two ways: ① download the .doc file and open it; ② copy as MathML and paste into Word — Word converts MathML into a native, editable equation (recommended).

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