Free content marketing tools: 37 browser-based checkers, generators and calculators

Free online content marketing tools for people who create

Thirty seven checkers, generators, calculators and tests that run in your browser. No signup, no limits, and nothing you paste leaves your machine.

Writing and editing

Schema and SEO (Coming Soon!)

Planning and business (Coming Soon!)

Formatting and utilities (Coming Soon!)

Learn and test (Coming Soon!)

Why these tools exist

Every one of these started as a check we ran by hand for a client: does the snippet truncate, is the FAQ block valid, is the draft mostly passive voice, will the AI crawlers even see the page. Doing them by hand is slow and nobody else on the team learns anything. A tool that shows the answer instantly, and explains the rule underneath it, fixes both problems.

None of them call an external service. That keeps them fast, keeps your drafts private, and means they will still work when the free tier of some other tool disappears. If you find a bug or a limit that has changed, tell us and it gets fixed.

Frequently asked questions

Are these tools really free?

Yes. There is no account, no usage limit and no paid tier. They exist because the same checks come up in every content project we work on, and a tool is faster to share than a checklist.

Is my text stored or sent anywhere?

No. Every tool runs entirely in your browser with plain JavaScript. Nothing you paste is transmitted to a server. A few tools keep your own settings (such as a saved UTM history) in your browser’s local storage, which you can clear at any time.

Can I link to or embed these tools?

You are welcome to link to any tool page. If you want to embed one on your own site or use the code, get in touch through the contact page.

How often are the tools updated?

Whenever a platform changes a limit or a format (character limits, snippet widths, schema types) we update the affected tool and note the change on its page.

What should I build next?

Tell us. The tools on this page came from questions clients ask; if a check you do by hand is missing, send it over.