diff --git a/src/rank/criterion/sum_of_typos.rs b/src/rank/criterion/sum_of_typos.rs
index 5d98a42e7..0f7edbbd5 100644
--- a/src/rank/criterion/sum_of_typos.rs
+++ b/src/rank/criterion/sum_of_typos.rs
@@ -7,17 +7,20 @@ use crate::rank::RawDocument;
 
 #[inline]
 fn sum_matches_typos(query_index: &[u32], distance: &[u8]) -> isize {
-    let mut sum_typos = 0;
-    let mut number_words = 0;
+    let mut number_words = 0.0;
+    let mut sum_typos = 0.0;
     let mut index = 0;
 
     for group in query_index.linear_group_by(PartialEq::eq) {
-        sum_typos += distance[index] as isize;
-        number_words += 1;
+        let typo = distance[index] as f32;
+        sum_typos += (typo + 1.0).log10();
+        number_words += 1.0_f32;
         index += group.len();
     }
 
-    sum_typos - number_words
+    let out = number_words / (sum_typos + 1.0);
+
+    (out * 1000.0) as isize
 }
 
 #[derive(Debug, Clone, Copy)]
@@ -37,7 +40,7 @@ impl Criterion for SumOfTypos {
             sum_matches_typos(query_index, distance)
         };
 
-        lhs.cmp(&rhs)
+        lhs.cmp(&rhs).reverse()
     }
 }
 
@@ -57,9 +60,9 @@ mod tests {
         let query_index1 = &[0, 1];
         let distance1 = &[1, 0];
 
-        let lhs = sum_matches_typos(query_index0, distance0);
-        let rhs = sum_matches_typos(query_index1, distance1);
-        assert_eq!(lhs.cmp(&rhs), Ordering::Less);
+        let doc0 = sum_matches_typos(query_index0, distance0);
+        let doc1 = sum_matches_typos(query_index1, distance1);
+        assert_eq!(doc0.cmp(&doc1).reverse(), Ordering::Less);
     }
 
     // typing: "bouton manchette"
@@ -74,9 +77,9 @@ mod tests {
         let query_index1 = &[0];
         let distance1 = &[0];
 
-        let lhs = sum_matches_typos(query_index0, distance0);
-        let rhs = sum_matches_typos(query_index1, distance1);
-        assert_eq!(lhs.cmp(&rhs), Ordering::Less);
+        let doc0 = sum_matches_typos(query_index0, distance0);
+        let doc1 = sum_matches_typos(query_index1, distance1);
+        assert_eq!(doc0.cmp(&doc1).reverse(), Ordering::Less);
     }
 
     // typing: "bouton manchztte"
@@ -91,8 +94,8 @@ mod tests {
         let query_index1 = &[0];
         let distance1 = &[0];
 
-        let lhs = sum_matches_typos(query_index0, distance0);
-        let rhs = sum_matches_typos(query_index1, distance1);
-        assert_eq!(lhs.cmp(&rhs), Ordering::Equal);
+        let doc0 = sum_matches_typos(query_index0, distance0);
+        let doc1 = sum_matches_typos(query_index1, distance1);
+        assert_eq!(doc0.cmp(&doc1).reverse(), Ordering::Less);
     }
 }