diff --git a/Cargo.lock b/Cargo.lock
index 12af7ea..46ab217 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -343,6 +343,7 @@ dependencies = [
  "log",
  "matching_handlers",
  "model",
+ "parsing",
  "pathfinding",
  "unordered-pair",
  "uuid",
diff --git a/matching/Cargo.toml b/matching/Cargo.toml
index 8058d77..6f00aa7 100644
--- a/matching/Cargo.toml
+++ b/matching/Cargo.toml
@@ -14,3 +14,4 @@ pathfinding = "4.9.1"
 
 [dev-dependencies]
 uuid = { workspace = true }
+parsing = { path = "../parsing" }
diff --git a/matching/src/lib.rs b/matching/src/lib.rs
index bda7aa1..6aa2842 100644
--- a/matching/src/lib.rs
+++ b/matching/src/lib.rs
@@ -47,21 +47,18 @@ pub fn calculate_matchings<'a>(
             let is_perfect_match = kind_left == kind_right && value_left == value_right;
             Matchings::from_single(
                 UnorderedPair(left, right),
-                MatchingEntry::new(is_perfect_match.into(), is_perfect_match),
+                MatchingEntry::new(left, right, is_perfect_match.into()),
             )
         }
-        (_, _) => Matchings::from_single(UnorderedPair(left, right), MatchingEntry::new(0, false)),
+        (_, _) => Matchings::empty(),
     }
 }
 
 #[cfg(test)]
 mod tests {
+    use crate::{calculate_matchings, matching_configuration::MatchingConfiguration};
     use model::{cst_node::Terminal, CSTNode, Point};
 
-    use crate::{
-        calculate_matchings, matching_configuration::MatchingConfiguration, MatchingEntry,
-    };
-
     #[test]
     fn two_terminal_nodes_matches_with_a_score_of_one_if_they_have_the_same_kind_and_value() {
         let left = CSTNode::Terminal(Terminal {
@@ -84,10 +81,9 @@ mod tests {
         let matching_configuration = MatchingConfiguration::default();
         let matchings = calculate_matchings(&left, &right, &matching_configuration);
 
-        assert_eq!(
-            Some(&MatchingEntry::new(1, true)),
-            matchings.get_matching_entry(&left, &right)
-        )
+        let left_right_matching = matchings.get_matching_entry(&left, &right).unwrap();
+        assert_eq!(1, left_right_matching.score);
+        assert!(left_right_matching.is_perfect_match);
     }
 
     #[test]
@@ -112,9 +108,8 @@ mod tests {
         let matching_configuration = MatchingConfiguration::default();
         let matchings = calculate_matchings(&left, &right, &matching_configuration);
 
-        assert_eq!(
-            Some(&MatchingEntry::new(0, false)),
-            matchings.get_matching_entry(&left, &right)
-        )
+        let left_right_matching = matchings.get_matching_entry(&left, &right).unwrap();
+        assert_eq!(0, left_right_matching.score);
+        assert!(!left_right_matching.is_perfect_match);
     }
 }
diff --git a/matching/src/matching_entry.rs b/matching/src/matching_entry.rs
index a2757e8..1f06b34 100644
--- a/matching/src/matching_entry.rs
+++ b/matching/src/matching_entry.rs
@@ -1,3 +1,5 @@
+use model::CSTNode;
+
 #[derive(Clone, Debug, PartialEq, Eq)]
 pub struct MatchingEntry {
     pub score: usize,
@@ -5,10 +7,10 @@ pub struct MatchingEntry {
 }
 
 impl MatchingEntry {
-    pub fn new(score: usize, is_perfect_match: bool) -> Self {
+    pub fn new(left: &CSTNode, right: &CSTNode, score: usize) -> Self {
         MatchingEntry {
             score,
-            is_perfect_match,
+            is_perfect_match: (2 * score) == (left.get_tree_size() + right.get_tree_size()),
         }
     }
 }
diff --git a/matching/src/matchings.rs b/matching/src/matchings.rs
index 2435fc0..e100740 100644
--- a/matching/src/matchings.rs
+++ b/matching/src/matchings.rs
@@ -118,7 +118,10 @@ mod tests {
         });
 
         let mut matchings = HashMap::new();
-        matchings.insert(UnorderedPair(&a_node, &a_node), MatchingEntry::new(1, true));
+        matchings.insert(
+            UnorderedPair(&a_node, &a_node),
+            MatchingEntry::new(&a_node, &a_node, 1),
+        );
 
         assert_eq!(
             Some(Matching {
diff --git a/matching/src/ordered/mod.rs b/matching/src/ordered/mod.rs
index b4b8810..cbe27bf 100644
--- a/matching/src/ordered/mod.rs
+++ b/matching/src/ordered/mod.rs
@@ -80,10 +80,7 @@ pub fn calculate_matchings<'a>(
 
             let mut matchings = Matchings::from_single(
                 UnorderedPair(left, right),
-                MatchingEntry::new(
-                    matrix_m[m][n] + root_matching,
-                    left.contents() == right.contents(),
-                ),
+                MatchingEntry::new(left, right, matrix_m[m][n] + root_matching),
             );
 
             while i >= 1 && j >= 1 {
@@ -108,7 +105,7 @@ pub fn calculate_matchings<'a>(
 
 #[cfg(test)]
 mod tests {
-    use crate::{matching_entry::MatchingEntry, *};
+    use crate::MatchingConfiguration;
     use model::{
         cst_node::{NonTerminal, Terminal},
         language, CSTNode, Language, Point,
@@ -144,10 +141,10 @@ mod tests {
         let matching_configuration = MatchingConfiguration::default();
         let matchings = super::calculate_matchings(&left, &right, &matching_configuration);
 
-        assert_eq!(
-            Some(&MatchingEntry::new(1, true)),
-            matchings.get_matching_entry(&child, &child)
-        )
+        let child_matching = matchings.get_matching_entry(&child, &child);
+        assert!(child_matching.is_some());
+        assert_eq!(1, child_matching.unwrap().score);
+        assert!(child_matching.unwrap().is_perfect_match)
     }
 
     #[test]
@@ -188,11 +185,9 @@ mod tests {
 
         let matching_configuration = MatchingConfiguration::from(Language::Java);
         let matchings = super::calculate_matchings(&left, &right, &matching_configuration);
-
-        assert_eq!(
-            None,
-            matchings.get_matching_entry(&left_child, &right_child)
-        )
+        assert!(matchings
+            .get_matching_entry(&left_child, &right_child)
+            .is_none())
     }
 
     #[test]
@@ -234,10 +229,9 @@ mod tests {
         let matching_configuration = MatchingConfiguration::from(language::Language::Java);
         let matchings = super::calculate_matchings(&left, &right, &matching_configuration);
 
-        assert_eq!(
-            Some(&MatchingEntry::new(2, false)),
-            matchings.get_matching_entry(&left, &right)
-        )
+        let left_right_matchings = matchings.get_matching_entry(&left, &right).unwrap();
+        assert_eq!(2, left_right_matchings.score);
+        assert!(!left_right_matchings.is_perfect_match);
     }
 
     #[test]
@@ -271,10 +265,9 @@ mod tests {
         let matching_configuration = MatchingConfiguration::from(language::Language::Java);
         let matchings = super::calculate_matchings(&left, &right, &matching_configuration);
 
-        assert_eq!(
-            Some(&MatchingEntry::new(2, true)),
-            matchings.get_matching_entry(&left, &right)
-        )
+        let left_right_matchings = matchings.get_matching_entry(&left, &right).unwrap();
+        assert_eq!(2, left_right_matchings.score);
+        assert!(left_right_matchings.is_perfect_match);
     }
 
     #[test]
@@ -317,14 +310,14 @@ mod tests {
         let matching_configuration = MatchingConfiguration::default();
         let matchings = super::calculate_matchings(&left, &right, &matching_configuration);
 
-        assert_eq!(
-            Some(&MatchingEntry::new(2, true)),
-            matchings.get_matching_entry(&intermediate, &intermediate)
-        );
+        let intermediate_matching = matchings
+            .get_matching_entry(&intermediate, &intermediate)
+            .unwrap();
+        assert_eq!(2, intermediate_matching.score);
+        assert!(intermediate_matching.is_perfect_match);
 
-        assert_eq!(
-            Some(&MatchingEntry::new(3, true)),
-            matchings.get_matching_entry(&left, &right)
-        )
+        let left_right_matching = matchings.get_matching_entry(&left, &right).unwrap();
+        assert_eq!(3, left_right_matching.score);
+        assert!(left_right_matching.is_perfect_match);
     }
 }
diff --git a/matching/src/unordered/assignment_problem.rs b/matching/src/unordered/assignment_problem.rs
index bba1ec0..eb0d973 100644
--- a/matching/src/unordered/assignment_problem.rs
+++ b/matching/src/unordered/assignment_problem.rs
@@ -84,10 +84,7 @@ fn solve_assignment_problem<'a>(
 
     result.extend(Matchings::from_single(
         UnorderedPair(left, right),
-        MatchingEntry {
-            score: max_matching as usize + 1,
-            is_perfect_match: left.contents() == right.contents(),
-        },
+        MatchingEntry::new(left, right, max_matching as usize + 1),
     ));
 
     result
diff --git a/matching/src/unordered/unique_label.rs b/matching/src/unordered/unique_label.rs
index cafc136..5c961f8 100644
--- a/matching/src/unordered/unique_label.rs
+++ b/matching/src/unordered/unique_label.rs
@@ -51,10 +51,7 @@ pub fn calculate_matchings<'a>(
 
             result.extend(Matchings::from_single(
                 UnorderedPair(left, right),
-                MatchingEntry {
-                    score: sum + root_matching,
-                    is_perfect_match: left.contents() == right.contents(),
-                },
+                MatchingEntry::new(left, right, sum + root_matching),
             ));
 
             result
diff --git a/matching/tests/perfect_matching.rs b/matching/tests/perfect_matching.rs
new file mode 100644
index 0000000..4bffd4d
--- /dev/null
+++ b/matching/tests/perfect_matching.rs
@@ -0,0 +1,55 @@
+use matching::matching_configuration::MatchingConfiguration;
+use model::language::Language;
+use parsing::ParserConfiguration;
+
+#[test]
+fn the_perfect_matching_calculation_is_correct() -> Result<(), Box<dyn std::error::Error>> {
+    let config = ParserConfiguration::from(Language::Java);
+    let left = parsing::parse_string(
+        r#"""
+            public class Main {
+                static {
+                    int x = 2;
+                }
+
+                public static void main() {
+                    int a = 0;
+                }
+
+                public static void teste() {
+                    
+                }
+            }
+        """#,
+        &config,
+    )?;
+
+    let right = parsing::parse_string(
+        r#"""
+            public class Main {
+                public static void teste() {
+                    
+                }
+                static {
+                    int x = 2;
+                }
+
+                public static void main() {
+                    int a = 0;
+
+                }
+            }
+        """#,
+        &config,
+    )?;
+
+    let matching_configuration = MatchingConfiguration::from(Language::Java);
+    let matchings = matching::calculate_matchings(&left, &right, &matching_configuration);
+    assert!(
+        matchings
+            .get_matching_entry(&left, &right)
+            .unwrap()
+            .is_perfect_match
+    );
+    Ok(())
+}
diff --git a/model/src/cst_node.rs b/model/src/cst_node.rs
index e8c99f5..b615fb7 100644
--- a/model/src/cst_node.rs
+++ b/model/src/cst_node.rs
@@ -48,6 +48,22 @@ impl CSTNode<'_> {
             CSTNode::NonTerminal(node) => node.end_position,
         }
     }
+
+    fn get_subtree_size(&self) -> usize {
+        match self {
+            CSTNode::Terminal(_) => 0,
+            CSTNode::NonTerminal(node) => node
+                .children
+                .iter()
+                .fold(node.children.len(), |acc, child| {
+                    acc + child.get_subtree_size()
+                }),
+        }
+    }
+
+    pub fn get_tree_size(&self) -> usize {
+        self.get_subtree_size() + 1
+    }
 }
 
 #[derive(Debug, Default, Clone)]