Free TF-IDF Tool for SEO
See the terms the top-ranking pages use for any keyword — and what your content is missing. RankNibbler's free TF-IDF tool reads the real top Google results, scores the vocabulary those pages share, compares your own page, and even shows the backlinks behind each result. No guessing what to write, and no Surfer or Clearscope subscription.
What is TF-IDF in SEO?
TF-IDF stands for term frequency–inverse document frequency. It's a classic information-retrieval measure of how important a word is to a topic: how often a page uses the word (term frequency), weighed against how common that word is across all pages (inverse document frequency). A word that's everywhere — the, and, for — scores low; a word that's rare in general but frequent on pages about your topic scores high.
In SEO, that's exactly what you want to know: which terms genuinely define a topic in the eyes of the pages that already rank. (This is the SEO use of TF-IDF — distinct from its data-science life in machine learning and NLP, which is a different rabbit hole.)
TF-IDF vs keyword density
They're often confused, but they answer different questions. Keyword density just counts how often a word appears as a percentage of the page — which is why it over-values filler. If you measured density, the would look like your most "important" word on nearly every page.
TF-IDF fixes that by discounting words that appear everywhere. It surfaces the terms that are common on your topic but uncommon in general — the words that actually signal you've covered the subject. So instead of "use your keyword X times," you get a ranked list of the real vocabulary a topic demands.
How to use the TF-IDF tool
Three inputs, and you get a ranked term list back:
1. Enter your keyword
Type the keyword you want to rank for, and pick the country the results should come from.
2. Choose how many results to analyse
Analyse the top 3, 7 or 10 Google results for that keyword — more results give a broader picture of the topic's vocabulary.
3. Add your page (optional)
Paste your own URL to compare your page directly against the ranking pages and see the terms you're missing.
4. Read the terms and fill the gaps
You get the terms and phrases the ranking pages use, ranked by TF-IDF weight, alongside your own usage. Work the relevant ones into your content naturally — TF-IDF is a guide to coverage, not a quota to stuff.
Find the terms your content is missing
The real payoff is the comparison. Add your URL and the tool lines your page up against the top results, so the content gaps jump out: the topically-important terms the ranking pages all use that yours barely mentions. That's your shortlist — the concepts to add or expand so your page covers the subject as fully as the ones already winning the SERP.
See the backlinks behind each result
Terms aren't the whole story — links matter too. For each ranking result the tool also shows its backlinks and referring domains, so you can see why those pages rank, not just what they say. If the top results are all heavily linked, you'll know that matching their content alone won't be enough — and you can plan accordingly.
Is TF-IDF still relevant in 2026?
An honest answer, because it's a fair question. TF-IDF is an older technique, and Google's ranking has long since moved past it toward language models and entities — Google's own John Mueller has said plainly that it's an old metric and not something to chase. So no: matching a TF-IDF "score" will not rank you, and any tool that implies otherwise is overselling.
What TF-IDF still does brilliantly is research. It's one of the fastest, most interpretable ways to see the vocabulary a topic actually demands and to catch coverage gaps before you publish — a sanity check, not a magic dial. Use it the right way: as a starting point for genuine topic depth and the entities a subject involves, alongside writing for real intent. That's how it earns its place in 2026, even in the age of AI search.
Frequently asked questions
What is TF-IDF in SEO?
Term frequency–inverse document frequency: a way to measure which words matter to a topic by how often the ranking pages use them, weighed against how common those words are everywhere. In SEO it's used to see the vocabulary a topic demands — not to be confused with its data-science use in NLP.
How do I use TF-IDF to optimise content?
Enter a keyword (and optionally your page URL); the tool reads the top Google results, scores their terms, and shows the important ones you're under-using. Add them naturally where they fit — never stuff them in.
What's the difference between TF-IDF and keyword density?
Keyword density just counts how often a word appears. TF-IDF weighs that against how common the word is across pages, so it surfaces the terms that actually define a topic and ignores filler like the and and.
Is TF-IDF still relevant for SEO in 2026?
Yes, as a content-research signal — not a ranking dial. Google long ago built past plain TF-IDF, but it's still one of the fastest, most readable ways to check topic coverage and catch gaps before you publish.
Is TF-IDF a Google ranking factor?
Not directly. Google's John Mueller has said it's an old metric and not something to chase. Use it to spot vocabulary gaps, not to hit a target score.
Is there a free TF-IDF tool?
Yes — RankNibbler's TF-IDF tool is free, with a small daily run limit, and it saves your report history. No Surfer or Clearscope subscription needed.
How many top results does the tool analyse?
You choose the top 3, 7 or 10 Google results for your keyword and country.
Can I compare my own page to the top-ranking pages?
Yes — add your URL and the tool shows the important terms you're missing or under-using versus the pages that already rank, plus the backlinks and referring domains for each result.
Run your first TF-IDF analysis
It's free, and it sits alongside the rest of your SEO tools.