Changelog or Change Log: One Word or Two?

Short answer: in software, it’s changelog, one word. The two-word “change log” isn’t wrong, but it’s no longer the convention developers expect.

If you’ve ever paused mid-sentence wondering whether to write “changelog” or “change log,” you’re not alone. It’s one of those small style decisions that feels like it should have a clean rule. It does, mostly.

The one-word form won

In software, changelog as a single word is the standard. It’s the spelling baked into Keep a Changelog, the convention most projects follow. It’s how Git, GitHub, npm, and nearly every developer tool refer to the file. Open almost any open-source repo and you’ll find a CHANGELOG.md sitting in the root, not a CHANGE LOG.md.

This is how English compounds usually evolve. Two words that keep getting used together drift into a hyphenated form, then close up entirely. “Web site” became “website.” “E-mail” became “email.” “Change log” became “changelog.” The closed compound signals that this is one specific thing, a recognized artifact, not just any log that happens to track changes.

When “change log” as two words still fits

The two-word form isn’t a mistake. It’s older, it’s grammatically correct, and it still shows up in places where a change log is a formal record rather than a product update feed:

Regulated industries like pharma, aerospace, and medical devices, where a change log is part of an audit trail
ITIL and IT service management, where change logs document approved changes to infrastructure
Quality management and manufacturing, where the term predates software entirely

In those contexts, “change log” reads as correct and even expected. The distinction is roughly: a change log is a compliance document, a changelog is what your users read to see what’s new. If you’re writing release notes for a product, you want the second one. (Related: changelog vs release notes, which trips people up for similar reasons.)

What about the dictionary?

Dictionaries lag usage by years, sometimes decades, so several still list “change log” as two words or omit “changelog” entirely. Don’t let that talk you out of the one-word form. Spelling conventions in technical writing are set by how practitioners actually write, and on that score the question is settled. Your readers type “changelog” into search and into their codebases. Meet them there.

Capitalization

Keep it lowercase in running text: we updated the changelog. Capitalize it only when normal rules call for it:

At the start of a sentence
In a title or heading using title case
As the proper name of a page or feature, like a nav link that reads Changelog

There’s no reason to write “ChangeLog” with an internal capital. That camel-case form lingers in a few old Unix projects, but it looks dated now and you should avoid it in anything user-facing.

Does the spelling matter for SEO?

Not much. Google understands that “changelog” and “change log” mean the same thing and returns nearly identical results for both queries. What actually helps is consistency: pick one spelling and use it everywhere, in your headings, your URLs, and your body copy, instead of splitting signals between two forms. Since the one-word version is what people search and expect, that’s the one to standardize on.

The bottom line

Write changelog, one word, lowercase, for anything software-related. Reserve “change log” for formal compliance or audit contexts where it’s genuinely the right term. Then be consistent about it. The spelling is a small thing, but consistency is what makes your writing look considered rather than careless, which is exactly the impression you want a well-written changelog to give.

If you’d rather not think about any of this every release, ReleasePad drafts your changelog from your GitHub commits and keeps the format and spelling consistent for you. You can also grab one of our free release notes templates to start from a clean structure.

Frequently Asked Questions

Is it changelog or change log?

In software, the one-word spelling — changelog — is standard. It's the form used by the Keep a Changelog convention, by Git and GitHub, and by virtually every developer tool that ships release notes. The two-word form, change log, is older and still grammatically correct, but it now reads as dated or non-technical to most developer audiences.

Is 'change log' as two words ever correct?

Yes. 'Change log' as two words is correct standard English and still appears in regulated, manufacturing, ITIL, and quality-management contexts where a change log is a formal audit record. It isn't wrong — it just isn't the convention software teams use for a user-facing changelog of product updates.

Is changelog one word in the dictionary?

Major dictionaries have been slower than the software industry to adopt the closed compound, so you'll still find 'change log' listed in some references. But usage drives spelling, and in technical writing the one-word 'changelog' has won decisively. Follow your audience, not the dictionary lag.

Should I write Changelog or changelog — capitalized or lowercase?

Lowercase 'changelog' in running text. Capitalize it only at the start of a sentence, in a heading or title using title case, or when it's the proper label of a specific page or feature, such as a navigation link reading 'Changelog'.

Does the spelling affect SEO?

Barely. Google treats 'changelog' and 'change log' as close variants and serves nearly identical results for both. Pick the one-word form because that's what your readers type and expect, then use it consistently across your site, headings, and URLs rather than splitting signals between two spellings.