Calculate Keyword Effectiveness Index from monthly search volume and competition, or rank multiple keywords by KEI for SEO planning.
Keyword Effectiveness Index Formula
The calculator uses the standard KEI formula introduced by Sumantra Roy.
KEI = (Monthly Search Volume)^2 / Competition
- KEI = Keyword Effectiveness Index score
- Monthly Search Volume = average monthly searches for the keyword
- Competition = number of competing pages, allintitle results, or app/store listings
In Single keyword mode, you enter one keyword with its volume and competition number. The calculator squares the volume, divides by competition, and returns a single score with an opportunity label.
In Compare keywords mode, you paste a comma-separated list (keyword, volume, competition) and the calculator runs the same formula on each row, then sorts the list from highest to lowest KEI. Only compare scores that use the same competition source, since allintitle counts produce much smaller denominators than broad page counts and inflate the KEI.
Reference Tables
Use the score band table to interpret a single result. Use the source table to keep your competition numbers consistent.
| KEI Score | Interpretation | Action |
|---|---|---|
| Below 10 | Low opportunity | Skip unless intent is very valuable |
| 10 to 19 | Borderline | Compare against other candidates |
| 20 to 99 | Promising | Worth targeting in your content plan |
| 100 to 999 | Strong | Prioritize if intent matches |
| 1000+ | Very strong | Verify the competition number first |
| Competition Source | How to get it | Typical scale |
|---|---|---|
| Competing pages | Plain Google search result count | Thousands to millions |
| allintitle | allintitle:”keyword” search | Hundreds to tens of thousands |
| App/store listings | App Store or Play Store result count | Tens to thousands |
Example and FAQ
Example. A keyword has 1,200 monthly searches and 45,000 competing pages.
KEI = 1,200² ÷ 45,000 = 1,440,000 ÷ 45,000 = 32. That falls in the promising band, so it is worth targeting if the intent fits your page.
Why is the volume squared? Squaring weights demand more heavily than supply. A keyword with double the searches becomes four times as attractive at the same competition level, which matches how traffic potential scales in practice.
Can I compare a KEI from allintitle to one from broad pages? No. The denominators differ by orders of magnitude. Stick to one source per comparison set.
What competition number should I use for app store keywords? Use the listing count returned for that exact phrase in the relevant store. Keep the same store across all keywords you rank.
Is a higher KEI always better? Not always. A high score can come from a tiny competition number that is unreliable. Check the search intent and the actual results page before committing to a keyword.