diff --git a/board-network/src/protocol.rs b/board-network/src/protocol.rs
index 47c88d7..b97eb3e 100644
--- a/board-network/src/protocol.rs
+++ b/board-network/src/protocol.rs
@@ -51,6 +51,8 @@ pub enum ServerMessage {
     PlayerTurn(usize),
     /// Update the current hand of the player
     SyncHand(Vec<TileRef>),
+    /// Update the score of the n-th player.
+    SyncScore(usize, u32),
     /// Informs that a tile has been placed
     TilePlaced(Position2dRef, TileRef),
     /// Informs that a tile has been removed
diff --git a/board-server/src/room.rs b/board-server/src/room.rs
index 8d2f8ba..b43228d 100644
--- a/board-server/src/room.rs
+++ b/board-server/src/room.rs
@@ -6,6 +6,7 @@ use board_shared::deck::RngDeck;
 use board_shared::expr::is_valid_guess;
 use board_shared::game::Hand;
 use board_shared::position::Position2d;
+use board_shared::score::calc_score;
 use board_shared::tile::Tile;
 use futures::channel::mpsc::{UnboundedReceiver, UnboundedSender};
 use futures::StreamExt;
@@ -189,6 +190,7 @@ impl Room {
                 .hand
                 .complete(&mut self.deck)
                 .ok();
+            self.on_validated_move(self.active_player, &diff);
             self.next_player();
         } else {
             self.send(
@@ -198,6 +200,23 @@ impl Room {
         }
     }
 
+    fn on_validated_move(&mut self, player_id: usize, diff: &[Position2d]) {
+        let tiles_placed = diff
+            .iter()
+            .map(|&pos| {
+                self.board
+                    .get(pos.x, pos.y)
+                    .expect("A placed tile should not be empty.")
+            })
+            .collect::<Vec<Tile>>();
+        self.players[player_id].score += calc_score(&tiles_placed);
+        self.broadcast(ServerMessage::SyncScore(
+            player_id,
+            self.players[player_id].score,
+        ));
+        self.validated_board = self.board.clone();
+    }
+
     fn reset_player_moves(&mut self) {
         let diff = self.board.difference(&self.validated_board);
         for pos in diff {
diff --git a/board-shared/src/lib.rs b/board-shared/src/lib.rs
index 41efeea..603693e 100644
--- a/board-shared/src/lib.rs
+++ b/board-shared/src/lib.rs
@@ -7,4 +7,5 @@ pub mod game;
 mod lexer;
 mod parser;
 pub mod position;
+pub mod score;
 pub mod tile;
diff --git a/board-shared/src/score.rs b/board-shared/src/score.rs
new file mode 100644
index 0000000..9a4313b
--- /dev/null
+++ b/board-shared/src/score.rs
@@ -0,0 +1,79 @@
+use crate::tile::{Operator, Tile};
+
+/// Calculate the score for a given list of tiles.
+pub fn calc_score(tiles: &[Tile]) -> u32 {
+    tiles
+        .split(|tile| matches!(tile, Tile::Equals))
+        .map(calc_expression_score)
+        .sum()
+}
+
+fn calc_expression_score(tiles: &[Tile]) -> u32 {
+    let mut digit_score = 0u32;
+    let mut multiplier = 1u32;
+    for token in tiles {
+        match token {
+            Tile::Digit(_) => digit_score += 1,
+            Tile::Operator(op) => {
+                match op {
+                    Operator::Add | Operator::Subtract => multiplier = 2,
+                    Operator::Multiply => multiplier = 3,
+                    Operator::Divide => digit_score += 10,
+                };
+            }
+            _ => unreachable!(),
+        }
+    }
+    digit_score * multiplier
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tile::Digit;
+
+    use super::*;
+
+    #[test]
+    fn only_digits() {
+        assert_eq!(
+            calc_score(&[
+                Tile::Digit(Digit::new(7)),
+                Tile::Digit(Digit::new(8)),
+                Tile::Equals,
+                Tile::Digit(Digit::new(9)),
+                Tile::Digit(Digit::new(4)),
+            ]),
+            4
+        );
+    }
+
+    #[test]
+    fn calc_individually() {
+        assert_eq!(
+            calc_score(&[
+                Tile::Digit(Digit::new(4)),
+                Tile::Operator(Operator::Add),
+                Tile::Digit(Digit::new(5)),
+                Tile::Equals,
+                Tile::Digit(Digit::new(3)),
+                Tile::Operator(Operator::Multiply),
+                Tile::Digit(Digit::new(3)),
+            ]),
+            10
+        );
+    }
+
+    #[test]
+    fn diviser_add_to_original_sum() {
+        assert_eq!(
+            calc_score(&[
+                Tile::Digit(Digit::new(8)),
+                Tile::Operator(Operator::Divide),
+                Tile::Digit(Digit::new(4)),
+                Tile::Equals,
+                Tile::Digit(Digit::new(2)),
+            ]),
+            13
+        );
+    }
+}