キーワード密度チェッカー

What is a good keyword density?

There is no fixed percentage that guarantees rankings. Use density as a quality check, not a target. If a phrase appears too often, the text may feel unnatural. If it never appears, the page may not clearly match the topic.

Read more in our keyword density guide.

What keyword density is

キーワード density is the percentage of times a term appears relative to the total word count. A balanced density (between 1% and 3%) helps SEO ranking without falling into keyword stuffing.

Recommended density

• 1-2%: Ideal for long, competitive articles.
• 2-3%: Suitable for product and category pages.
• 3-5%: Only for very short-tail keywords in brief texts.
• +5%: Avoid. Risk of penalty for keyword stuffing.

How to use the checker

Paste your content into the text area. The tool automatically calculates the density of each relevant word and phrase. Identify your main keyword and check whether it falls within the recommended range.

Frequently asked questions

Does density affect SEO? Yes, but indirectly. Excessive density can be penalized, and very low density can signal that the content isn't relevant to the term.

Should I count keyword variations? Yes, variations and synonyms count too. The tool detects them automatically.

What's the difference between density and frequency? 密度 is a percentage; frequency is a raw count. 密度 is what matters for SEO.

Related guides

Word frequency analysis