Markdown + LaTeX Math on iPhone, Offline
Lecture notes, AI answers, research writeups — Markdown with formulas renders as a clean page with real math typography, entirely on your device.
Updated 2026-08-09
OpenHTML opens any .md or .markdown file as a beautifully typeset page and renders LaTeX math — inline $…$ and display $$…$$ — using KaTeX-quality output that is generated once, on import, into pure static HTML and MathML.
That last part matters: the rendered page contains zero JavaScript and needs zero network. Formulas display instantly, work in airplane mode, and can't call any CDN. No subscription, no account.
How to open a Markdown file with math
Share or open the file
Send the .md file to OpenHTML from Files, Mail, a chat app or your AI app's share sheet — or use “Open from Files” to read it once without importing.
Read it as a real page
Headings, tables, code blocks with syntax highlighting, task lists and math all render immediately. Adjust text size per document if you like.
Export or keep it
Save the file into your library, organize with folders and tags, or export the rendered page as a full-length PDF or long image (Pro).
Why offline math rendering is rare
Most Markdown apps that support formulas load MathJax or KaTeX from a CDN at view time — which means formulas silently break offline, and every document you read touches the network.
OpenHTML renders math once, at import, into static HTML + MathML. The result is a self-contained page: it looks the same on every open, works with no connection, and runs no scripts. If a single formula has a syntax error, only that formula falls back to source text — the rest of the document still renders.
Everything else in your Markdown
- GitHub-flavored tables, task lists, footnotes and fenced code blocks with highlighting.
- Images referenced next to the file are picked up automatically.
- AI answers copied as Markdown paste straight in — see AI-generated HTML for the HTML variant.
- Prefer the raw source? A one-tap source view shows the original Markdown with line numbers and search.
Everything stays on device: no accounts, no analytics, and rendered pages never load remote resources unless you explicitly allow it.
Frequently asked questions
Which math delimiters are supported?
Inline $…$ and \(…\), and display $$…$$ and \[…\]. Rendering happens at import into static output, so pages open instantly afterwards.
Does it work in airplane mode?
Yes. Math is rendered into the page itself — no CDN, no scripts, no network. Formulas look identical offline and online.
What happens to a formula with a typo?
Only that formula falls back to its source text, marked clearly. The rest of the document renders normally — one bad equation never blanks the page.
Can I export the rendered result?
With the one-time Pro purchase you can export any page — including rendered math — as a full-length PDF or long image.
Read Markdown the way it deserves
Formulas, tables and code — typeset cleanly, rendered offline, private by default.
Download OpenHTMLFree on the App Store — core viewing needs no purchase.