Add hierarchical numbering to headings: 1. Section → 1.1 Subsection → 1.1.1 Sub-sub. Configurable.
0 headings numbered
Free Markdown Auto-Number Headings adds hierarchical numbering to every heading in a Markdown document. H1 becomes 1, H2 becomes 1.1, H3 becomes 1.1.1, and so on. Configurable start level, max depth, separator character, and automatic removal of existing numbers.
Privacy: This tool runs entirely in your browser. Your text is never uploaded, logged, or cached. Close the tab and it's gone. Verify in DevTools → Network: zero requests fire.
Numbering 30 headings by hand is tedious and error-prone. Add one section and every number after it shifts. This tool does it in milliseconds, for free, in your browser.
| Input | Output | Typical size | Speed | Login needed |
|---|---|---|---|---|
| Markdown (.md) | Markdown with numbered headings | Up to 5 MB | < 50 ms | No |
Here's what this free tool does in detail — every feature is built to solve real problems, runs entirely in your browser, and is free forever.
Headings are numbered in hierarchical order: # 1 Introduction, ## 1.1 Getting Started, ### 1.1.1 Prerequisites. Deeper counters reset when a higher-level heading appears. The separator is configurable (dot, dash, slash, or any text).
To audit your heading hierarchy first, use the Free Markdown Heading Shifter to normalize levels.
Set Start level and Max level to number only a subset of headings. For example, set start to 2 and max to 4 to number H2 through H4 while leaving H1 as a standalone title. Headings outside the range pass through untouched.
Pair with the Free Markdown TOC Generator to generate a matching table of contents after numbering.
The Remove existing option strips any leading digit-dot sequences from heading text before applying new numbers. Re-run the tool as many times as needed without accumulating duplicate prefixes. Toggle it off if your headings contain intentional leading numbers (e.g., '10 Downing Street').
For broader formatting cleanup, see the Free Markdown Formatter.
Fenced code blocks (``` and ~~~) are tracked and skipped. Headings inside code examples, shell comments, or Python docstrings are never numbered. Only real ATX-style headings at the document level are processed.
For renaming terms across the document (outside code blocks), try Free Markdown Find & Replace.
Drop a document with multiple heading levels into the input. Click Load example for a typical structure.
Adjust start level, max level, separator, and the remove-existing toggle.
Every heading in range now has a hierarchical number prepended.
Number RFC-style sections automatically so cross-references stay consistent.
Add chapter and section numbers to lesson plans in one pass.
Apply hierarchical clause numbering to Markdown-drafted agreements.
Re-number after restructuring without manually updating every heading.
Number chapters, sections, and subsections for academic formatting.
Yes. Free forever, no account required.
Hierarchical dot-notation by default: 1, 1.1, 1.1.1. The separator is configurable.
Yes. Set Start level to 2 and Max level to 3.
Yes. The Remove existing option strips old numbers before applying new ones.
No. Fenced code blocks are skipped entirely.
No. Runs 100% in your browser.