The 1–3% rule is outdated

The idea that a "correct" keyword density of 1–3% would help rankings was a rule-of-thumb from early SEO (pre-2011). Modern search engines use TF-IDF and semantic language models, not raw frequency, to measure topical relevance. Content optimized by stuffing keywords to a target percentage often performs worse than naturally written content.

TF-IDF: how search engines actually measure relevance

TF-IDF (Term Frequency – Inverse Document Frequency) is a statistical measure of how important a word is to a document relative to a corpus:

TF: how often the term appears in this document
IDF: how rare the term is across all documents in the index. Rare words score higher.
The product (TF × IDF) rewards documents that use distinctive, relevant terms - not just frequent ones.

A word like "the" has high TF but near-zero IDF (it appears everywhere). A specialized term like "metatarsal stress fracture" has lower TF but very high IDF, making it a strong signal of topic relevance.

Content optimization tips

Cover the topic thoroughly - use related terms, synonyms, and sub-topics naturally
Use your primary keyword in the title, H1, and first paragraph, then write naturally
Avoid repeating exact phrases; search engines understand semantic equivalents
Match search intent: informational queries need explanations; transactional queries need conversion-focused content

What is keyword density?

Keyword density is the ratio of how many times a word appears in your content to the total word count, expressed as a percentage. A density of 1–3% typically indicates natural usage; a word appearing 5%+ of the time may signal keyword stuffing, which modern search engines penalise.

How to use this tool

Paste the body text of your page (not the HTML source) into the text area. The tool strips stop words - high-frequency words like "the", "and", "of" that add no topical signal - so you can focus on the meaningful terms. Toggle to include them if you need a full frequency picture.

N-grams: single words vs phrases

Switching to 2-gram or 3-gram mode shows you multi-word phrases instead of single words. This is useful for spotting whether a key phrase like "running shoes" or "best coffee maker" appears often enough to signal topic relevance to search engines.