diff --git a/addon/calculator.hpp b/addon/calculator.hpp
index b1be101..6423e01 100644
--- a/addon/calculator.hpp
+++ b/addon/calculator.hpp
@@ -1,5 +1,6 @@
 #include <array>
 #include <vector>
+#include <string>
 
 struct PlayerStats {
     std::array<int, 10> handTypeSum;