You have an equation as a screenshot, in a slide, a scanned page or a PDF, and you want it as LaTeX. Most image-to-LaTeX tools upload the picture to a server. Here is how to do it entirely on your own computer, and what the alternatives are.

The quick way

  • Snip the equation. Press Ctrl+Alt+T anywhere on screen and drag a box around it,
    or drop an image file on the CatchTeX window. If the equation is in a PDF, open the PDF in CatchTeX
    (Ctrl+O) instead: the symbols are then read from the file itself, which is exact.

  • Pick the style with the chips above the preview: \[ \], $$,
    equation, equation*, $ or \( \). Turn on
    (n) to keep the paper's equation number as \tag{n}.

  • Check the compiled preview next to the code, fix anything in the editor if needed.

  • Copy LaTeX (Ctrl+Shift+C) and paste it into Overleaf or your editor.

E = ∫0∞ e−αx dx    (3)

snip ↓ LaTeX

\begin{equation}

E = \int_0^{\infty} e^{-\alpha x}\,dx

\tag{3} \end{equation}

What "offline" means here

The maths model (PP-FormulaNet-S, run with ONNX) and the text recognition (Tesseract) are part of
the installer and run on your processor. No account, no internet connection and no Python
installation are needed, and the image never leaves your computer. That matters for unpublished
work, theses under embargo and documents under a non-disclosure agreement.

How good is it?

On our test set of 30 equations rendered as images, all 30 results compile and the LaTeX matches
the original with 0.97 similarity on average. In practice: typical display equations come out right
or need a small fix; very long multi-line derivations and unusual notation need more checking. The
compiled preview makes mistakes easy to spot before you copy. Handwritten maths is not supported.

Other ways, compared

Tool Runs offline Setup Checked before you copy Cost
pix2tex (LaTeX-OCR) Yes Python, pip, model download No Free, open source
Mathpix Snip No, cloud App + account Rendered preview Free quota, then subscription (comparison)
SimpleTex and other web tools No, cloud Browser or app Preview Mostly free
ChatGPT, Claude, Gemini No, uploaded Account No; can change symbols silently Free tier / subscription
CatchTeX Yes One Windows installer Yes, compiled with built-in pdfLaTeX Free edition; Pro once

Tips

  • Snip tightly around the equation, but include the number on the right if you want to keep it.

  • A bigger image reads better: zoom in on a small equation before you snip it from the screen.

  • For equations inside a PDF, open the PDF in CatchTeX rather than taking a screenshot: exact
    symbols beat recognition.

  • Auto mode tells you when a snip looks like a table or text instead; click the suggested mode to
    re-read it.

Questions

Does it work on Mac or Linux?

Not yet: CatchTeX is for Windows, Mac and Linux. Join the Mac waitlist.
Can it read a whole page of equations?

Snip one equation (or one aligned block) at a time; that gives the cleanest LaTeX. For a page of
running text with inline maths, use Text mode.

Try it on your own paper

CatchTeX is free for Windows, Mac and Linux: every mode, works offline, nothing to set up.

[

Download CatchTeX free](https://catchtex.comdownload?ref=guide-image-latex)

Originally published at catchtex.com/guides/image-to-latex-offline.

CatchTeX runs offline on Windows, Mac and Linux. Download it free at catchtex.com.