HTM to JSON Converter
Processing entirely on your device — large files may take a moment.
HTM is the three-letter variant of the HTML extension, a leftover from DOS and Windows 3.x filename limits. The content is a standard web page. Convert tables to JSON when a website, app or API expects structured records with named fields.
Because the whole conversion happens on your device, it is instant, unlimited and genuinely private — no accounts, no watermarks, no files on anyone's server. Multiple files are converted in one go.
How HTM compares to JSON
| HTM | JSON | |
|---|---|---|
| Structure | Tag semantics | Trees of objects and arrays |
| Best for | Web pages and shareable documents | APIs, app data, config-as-code |
How to convert HTM to JSON
- 1
Select your files
Drag & drop your HTM files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to JSON". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted JSON file individually, or grab everything at once as a ZIP archive.
About the HTM format
HTML is the markup language of the web itself. A document is plain text decorated with tags that describe structure — headings, paragraphs, lists, links, tables, images — and browsers turn that structure into a rendered, styled page. It is both a format and a program target: CSS styles it and JavaScript makes it interactive.
As a document format, HTML's strength is universality: any device with a browser displays it, text stays selectable and searchable, and links make it navigable. Its weakness is that rendering depends on the surrounding CSS and viewport, so it is a flowing document, not a fixed-layout one — printing or archiving an HTML page is inherently an approximation.
+ Strengths
- ✓Displays on every device with a browser
- ✓Semantic structure: headings, links, tables, media
- ✓Text remains selectable, searchable and accessible
! Limitations
- −Final look depends on CSS and viewport
- −Not a fixed-layout or print format
- −Untrusted HTML must be sanitized before display
About the JSON format
JSON (RFC 8259, popularized by Douglas Crockford) is the lingua franca of program data. It has exactly six types — string, number, boolean, null, array, object — nested into trees, and every language on earth parses it natively. REST APIs, NoSQL documents, browser configuration, package manifests: if software talks to software, JSON is usually the sentence.
The spec is deliberately strict: double quotes only, no trailing commas, no comments. That rigidity makes parsers trivial and interop reliable, but it also makes JSON awkward for hand-edited config (people bolt comments on and break parsers) and its 1:1 text mapping keeps large files heavier than binary alternatives.
+ Strengths
- ✓Native parsing in every language
- ✓Six clear types, nesting as deep as needed
- ✓The default of APIs and modern tooling
! Limitations
- −No comments — poor fit for hand-edited config
- −Strict syntax: trailing commas and single quotes break it
- −Verbose; large files parse slowly
Why convert HTM to JSON?
Converting makes sense where the strengths of JSON meet what HTM cannot give you. Native parsing in every language Meanwhile Final look depends on CSS and viewport One pass through the converter above puts your file on the right side of that trade-off.
Frequently asked questions
Is this HTM to JSON converter really free?
Yes — completely free, with no sign-up, no watermark and no daily conversion limits. The site is supported by advertising.
Are my files uploaded to a server?
No. The conversion runs entirely inside your browser using WebAssembly, so your files never leave your device — that is what makes it instant and private.
Does it work on Windows, Mac, iPhone and Android?
Yes. Anything with a modern browser works: Windows, macOS, Linux, Android and iOS. No software installation is required.
Is there a file size limit for HTM to JSON?
The only limit is your device's memory, since nothing is uploaded. Files up to a few hundred megabytes work fine on a modern desktop browser; very large files simply take a little longer.
Are formulas, styles or multiple sheets converted?
No — this conversion extracts the data itself into JSON. Formulas are exported as their current values, styling is not carried over, and multi-sheet workbooks convert sheet by sheet. For full fidelity between spreadsheet formats, exchange within the same tool family.
How large can my HTM file be?
Since everything runs locally in your browser, the real limit is your device memory rather than an upload cap. Files up to a few hundred megabytes are usually fine on a modern computer; extremely large ones simply take longer.