You ask ChatGPT to explain a derivation. It produces something that looks like this:
The cost function is minimized when \nabla J(\theta) = 0, which gives the normal equation:
\[
\theta = (X^TX)^{-1}X^Ty
\]
In the chat window, that looks fine — ChatGPT renders it for you in place. But the moment you paste that text into Notion, Google Docs, Word, or your own notes app, you get raw symbols: backslashes, brackets, and dollar signs scattered across the page. The equation is gone. You're left with \theta = (X^TX)^{-1}X^Ty floating in plain text.
This is one of the most common frustrations for students, researchers, and engineers who actually try to use AI-generated math outside of the chat window. Here's why it happens — and how to fix it in one step.
Why AI Math Breaks Outside the Chat Window
Every AI uses its own dialect for formatting math. There is no standard.
- ChatGPT wraps block equations in
[ ... ]and inline math in( ... ) - Claude uses
\[ ... \]and\( ... \)— the LaTeX-standard backslash form - Gemini mixes styles depending on the response
- Grok follows its own conventions
None of these match the $$ ... $$ delimiter that most external renderers (Notion, KaTeX, MathJax, GitHub) actually expect. So when you paste AI output anywhere other than the chat interface, the renderer doesn't recognize the math markers and falls back to displaying raw text.
The same problem hits code blocks and tables. Most apps don't parse fenced code blocks from plain text, so your \``python` snippet becomes monospace gibberish instead of highlighted code.
The Fix: Repaper
Repaper is a free browser-based tool that does one thing well: it takes raw AI output and renders it into a clean, readable document — with properly typeset math, syntax-highlighted code, and formatted tables — then lets you export it as a PNG or PDF.
No account. No upload. Everything runs locally in your browser.
How to use it
Step 1 — Paste your AI response
Go to fileconvertiz.com/repaper. Copy any response from ChatGPT, Claude, Gemini, or Grok and paste it into the left panel. You don't need to clean it up or convert the formatting first — Repaper detects each AI's math dialect automatically.
Step 2 — Preview the result
The right panel renders the output within 200ms. Block equations appear as proper LaTeX via KaTeX. Code blocks get syntax highlighting for 100+ languages. Tables become readable, properly spaced grids. Headings, lists, and blockquotes all format correctly.
Step 3 — Export
- Copy as PNG — captures the preview at 2× resolution and copies it straight to your clipboard. Paste it into Notion, Google Docs, Slides, or any app that accepts images.
- Download PDF — opens a print-ready popup with the correct fonts and paginated layout. In the print dialog, choose "Save as PDF". Equations never break across lines, and code blocks never get split mid-function.
What Gets Rendered
Repaper handles everything an AI typically outputs:
Math — inline $...$ and display $$...$$ equations via KaTeX, including matrices, integrals, summations, Greek letters, fractions, square roots, aligned equation environments, and subscript/superscript notation.
Code — fenced code blocks with language tags (python, js, sql, bash, and 100+ more) rendered with full syntax highlighting.
Tables — GitHub Flavored Markdown tables turned into clean, readable grids.
Standard markdown — headings H1–H6, bold, italic, inline code, blockquotes, ordered and unordered lists, and horizontal rules.
Who This Helps Most
Students — Ask an AI to walk through a proof or solve a problem set, then export the response as a clean PDF for your notes. No more screenshotting a chat window.
Researchers — Copy an AI-generated equation derivation or data summary into a properly formatted document without manually fixing every delimiter.
Engineers and data scientists — Render an algorithm explanation with code and math side-by-side, then paste the image into a Confluence page or Notion doc.
Teachers — Turn an AI-generated worksheet or explanation into a printable PDF in one click, with no LaTeX knowledge required.
Your Text Stays Private
Repaper runs 100% client-side. When you paste text, it's processed entirely in JavaScript inside your browser tab — there is no server, no API call, and nothing is uploaded anywhere. This matters if you're pasting proprietary code, personal data, or confidential research notes from an AI conversation.
Close the tab and everything is gone from memory.
Frequently Asked Questions
Does this work with Claude and Gemini, not just ChatGPT? Yes. Each AI uses slightly different math delimiters. Repaper detects all of them automatically — just paste and it renders correctly regardless of which AI you're using.
Can I paste the PNG into Google Docs or Notion? Yes. Click "Copy Image" and then paste directly (Cmd+V / Ctrl+V) in any app that accepts images. The image is copied at 2× pixel density so it looks sharp on retina displays.
How do I save it as a PDF? Click "Download PDF". Your browser's print dialog opens — set the destination to "Save as PDF". The fonts, math, and layout are preserved exactly as shown in the preview.
Does it support matrices and Greek letters?
Yes. KaTeX supports the full LaTeX math vocabulary — \begin{bmatrix}, \int, \sum, \alpha, \frac, \sqrt, \begin{aligned}, and everything else you'd use in a real LaTeX document.
Is there a character or document length limit? No. Processing happens in your browser, so there's no server-imposed limit. Very long responses (thousands of words with dozens of equations) may take a second or two to render — that's expected.