Keyword density warnings in Yoast SEO and Rank Math
Both Yoast SEO and Rank Math measure how often your focus keyword appears compared with the length of your text. Yoast's Keyphrase density check is green from 0.5 to 3 percent and red above that, with a firm "Don't overoptimize!". Rank Math's Keyword Density test gives its best score between just over 1 and 2.5 percent, and fails anything under 0.5 or over 2.5 percent.
Google does not use keyword density as a ranking measure. Repeating a phrase until it hits a percentage can make a page read like spam, which is the real risk the upper limits guard against. Use these checks to catch two problems: a page that never names its topic, and a page that names it far too often.
Two formulas for the same idea
The plugins count matches differently, which is why the same post can pass one and fail the other.
Yoast counts a match when all the content words of your keyphrase appear in the same sentence, in any order. Several full matches in one sentence count separately. For texts of 100 words or more, it calculates a density: 0.5 to 3 percent is green, below 0.5 percent is red ("Focus on your keyphrase!"), and above 3 percent is red with a negative score, getting more negative above 4 percent. When Premium recognizes multiple word forms, the upper green limit rises to 3.5 percent. Short texts use counts instead: in a text under 51 words, one use is ideal and two is already too many.
Rank Math searches the text for your focus keywords and their combinations, then divides the number of matches by the word count. Its bands, from the plugin's source:
| Density | Rank Math result |
|---|---|
| Under 0.5% | Fail, reported as low |
| 0.5% to 0.75% | Fair |
| 0.76% to 1.0% | Good |
| Above 1.0% up to 2.5% | Best |
| Over 2.5% | Fail, reported as high |
Rank Math's knowledge base suggests aiming for 1 to 1.5 percent. Its own tooltip is more cautious: "There is no ideal keyword density percentage, but it should not be too high. The most important thing is to keep the copy natural."
A number from an earlier web
Keyword density comes from the early days of search, when ranking systems leaned heavily on how often a term appeared on a page. Because repetition worked, it was abused, and pages were stuffed with the same phrase in visible text, hidden text and footers.
Google's spam policies now name keyword stuffing explicitly as a violation. Google has also said, including in a well-known answer by Matt Cutts, that the first mentions of a term help it understand a page, and that each additional repetition helps less, until it starts to look like stuffing. There has never been a published ideal percentage.
Modern search understands synonyms, related terms and the overall topic of a passage. A page about espresso grinders that talks about burrs, grind size and retention is clearly about grinders even if the exact phrase appears three times.
Reading a low or high result
A low density usually means one of two things. Either the post really is about something slightly different from the keyword you set, and you should change the keyword, or you are writing around the topic with vague references like "it", "this tool" and "the process". Naming the thing plainly a few more times often improves clarity as well as the score.
A high density on a normal post is rarer, and worth checking for causes outside the prose:
- a repeated call-to-action block or signature that contains the phrase;
- product tables or specification lists where the name appears on every row;
- a short post where each use counts for a large share of the words.
Replace some repetitions with pronouns or natural variants, and trim boilerplate. Do not remove the term from places where a reader needs it, such as a heading or a step that names the product.
Where the two plugins disagree, between 2.5 and 3 percent, neither is more "right" for Google. Pick the result that reads best.
Density in Hydrogen SEO's score
Hydrogen SEO also includes density, as one fifth of its per-post SEO score. It counts how many times the focus keyword phrase appears in the text, ignoring case, and divides by the number of words. Full points need 0.5 to 2.5 percent; a keyword that appears but falls outside that range earns half; no focus keyword, or one that never appears, earns none.
The band is close to both plugins' ranges on purpose, and the docs say the same thing this page does: the score is a pre-publish review, not a target to game. If you move from Yoast or Rank Math, your focus keywords come across with the importer.
Common questions
What is the ideal keyword density?
There isn't one that search engines use. Yoast's green range is 0.5 to 3 percent and Rank Math's best range runs above 1 up to 2.5 percent, but those are plugin defaults. Write naturally and make sure the topic is named clearly.
Why does Rank Math say my density is high when Yoast is green?
Rank Math fails anything over 2.5 percent, while Yoast stays green up to 3 percent. They also count matches differently, so the same text can produce different percentages.
Does Rank Math count secondary keywords in density?
Rank Math's density test searches for the focus keywords and their combinations, and its knowledge base says the test applies to primary and secondary focus keywords.
Can keyword stuffing get a page penalized?
Yes. Keyword stuffing is listed in Google's spam policies, and pages that repeat terms unnaturally can rank lower or be removed from results in serious cases.