diff --git a/_search-plugins/knn/knn-score-script.md b/_search-plugins/knn/knn-score-script.md
index a2819f7568..a02e85defd 100644
--- a/_search-plugins/knn/knn-score-script.md
+++ b/_search-plugins/knn/knn-score-script.md
@@ -313,7 +313,7 @@ A space corresponds to the function used to measure the distance between two poi
   </tr>
   <tr>
     <td>innerproduct</td>
-    <td>\[ Distance(X, Y) = \sum_{i=1}^n (X_i - Y_i) \]</td>
+    <td>\[ Distance(X, Y) = \sum_{i=1}^n X_iY_i \]</td>
     <td>1 / (1 + Distance Function)</td>
   </tr>
   <tr>