Keyword Density & Word Frequency

How to Use the Keyword Density Checker

Paste your text and type the keyword to check. Leave the keyword blank to auto-pick the most frequent word. The Top 10 words list shows the overall vocabulary balance.

Use it as a quick editorial check for SEO drafts, landing pages, product copy and article outlines. The goal is not to hit a magic percentage; it is to spot accidental repetition, missing focus terms and wording that feels unnatural.

Examples

• English paragraph (18 words), keyword "the" → 4 occurrences / 22.22% density (a sign of stuffing)
• The SEO draft example above, keyword "keyword" → 3 occurrences / 18 total words / 16.67% density
• Leave the keyword blank → the most frequent word is auto-selected for the count and density
• Top 10 words → listed in descending order, e.g. "the 4 / dog 2 / fox 2 …"
• Case → "The" and "the" are merged into one word (case-insensitive)

Reading the Results

• Occurrences shows how many times the target keyword appears.
• Density shows that count as a share of total words.
• Top 10 words helps reveal overused filler words or repeated product terms.

What Counts as One Word

Only two kinds of runs are counted. A run of letters, digits and underscores is one word. A run of hiragana, katakana or kanji is cut into two-character pairs, each shifted by one character (東京に住む → 東京 京に に住 住む); a run of a single character stays one word. Everything else — symbols, spaces, full-width alphanumerics, half-width katakana — acts as a separator. Whatever you type in the keyword field never changes this split.

Why Japanese Is Counted in Two-Character Pairs

Japanese has no spaces between words, and this tool ships no morphological dictionary, so it cannot cut a sentence into meaningful words. Instead it cuts every run of kana and kanji into overlapping two-character pairs and uses the number of pairs as the total. Keeping each run as one word would report a total of 1 at 100.00% density for any text without separators, which tells you nothing.

The point is that the total and the Top 10 words never depend on the keyword. The denominator stays at 14 however you change the keyword, so you can try several keywords on the same text and line the densities up. In Japanese the Top 10 list is made of those pairs too: a draft containing キーワード three times reports キー, ーワ, ワー and ード at 3 each.

The trade-off is granularity. The denominator counts two-character pairs while the numerator counts the keyword itself, so a keyword that is not two characters long is measured on a different scale from the denominator. In the table above 東京 and 京 both report 3 occurrences at 21.43%, and the density alone cannot tell a two-character word from a single character. Read the Japanese density as a comparison between keywords inside one text, not as an absolute number.

Keyword Matching Rules

• An alphanumeric keyword matches whole words only. cat never matches category (in category cat it counts once).
• An alphanumeric keyword containing a space always returns zero, because a space never appears inside a word. Check phrases such as brown fox one word at a time.
• A keyword containing kana or kanji is counted as a substring of the text. It is searched in the raw text regardless of how the text was split, so 東京 inside 東京都 counts once (東京 東京タワー 東京都 東京 gives 4).
• Case is ignored. The and the are merged.
• Inflections, plurals and synonyms are never merged (dog and dogs are separate words). Check each spelling you care about.

Tokenization and SEO Limits

Because the tokenizer uses no morphological dictionary, the Japanese "total words" figure is not a linguistic word count: it is the number of two-character pairs. For space-delimited languages one word is one token, so the density reads directly as a share of the words. For Japanese, these gaps remain:

• Keywords of three characters or more: in 東京都に住む (5 total words) the keywords 東京都, 東京 and 都 all report 1 occurrence at 20.00%, so their differing lengths never show up in the density.
• Repeated identical characters: with the text 東東東 and the keyword 東東, occurrences are counted without overlap and report 1, while the Top 10 list shows the pair 東東 twice.
• Keywords of three characters or more never appear in the Top 10 words, because in Japanese the list only ever holds two-character pairs (or a single character when the run is one character long). Read those keywords from the occurrences and density figures instead.

Other keyword-density tools use morphological analysis or character counts as the denominator, so these percentages cannot be compared with theirs. Use them to compare keywords within one text, or to compare drafts against each other with the same keyword.

There is no universal keyword-density target that guarantees search ranking. Repeating a phrase to reach a percentage can make writing less useful. Prioritize clear headings and complete answers, and use the Character Counter for overall text statistics.

FAQ