Free Keyword Density Checker

How this tool computes its result

Total word count comes from matching `/[A-Za-z0-9]+/g` tokens in the content. For each keyword line, it counts exact-phrase regex matches (special characters escaped) case-insensitively; for multi-word keywords it separately counts consecutive-word matches joined with `\s+`, and for single-word keywords it counts exact token equality against the tokenized word list — then takes the max of the two counts. Density = count / totalWords * 100, rounded to 2 decimals. Status bands: ≥3% "high", 1–3% "optimal", 0.5–1% "low", 0–0.5% "very-low" (0% = keyword not found). The overall score averages a per-keyword score (100 for optimal, 70 for low, 30 for very-low/not-found, and for high a penalty of `min(density-2, 3) * 20` subtracted from 100, floored at 40).

Worked example

Content of 200 tokenized words with the keyword "SEO tools" appearing exactly 3 times as an exact phrase: density = 3/200*100 = 1.50% → status "optimal", score contribution 100. If instead the same keyword appeared 8 times in that 200-word content, density = 4% → status "high", penalty = min(4-2,3)*20 = 40, so that keyword's score = max(40, 100-40) = 60.

When not to use this tool

Word tokenization only matches alphanumeric runs (`/[A-Za-z0-9]+/g`), so it cannot meaningfully measure density for languages that do not use whitespace-delimited alphanumeric words (e.g. CJK text). It also does not strip HTML markup, so pasting rich content with tags inflates or skews both the word count and keyword matches.

Common mistakes

• - Entering near-duplicate keyword variants on separate lines (e.g. "SEO tool" and "SEO tools") — each line is tracked and scored independently instead of being aggregated into one metric.
• - Assuming density is computed against character count; it is count divided by the regex-tokenized word count, so keyword phrases glued to punctuation can undercount.
• - Not realizing the high-density penalty caps at a density-2-of-3 window — any density above roughly 5% scores identically (40) instead of degrading further, so 6% and 20% density look the same in the score.

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