diff --git a/src/pch.h b/src/pch.h
index 37596e14c..7821ee302 100644
--- a/src/pch.h
+++ b/src/pch.h
@@ -20,6 +20,7 @@
 #ifndef FUR_PCH_H
 #define FUR_PCH_H
 
+#define _USE_MATH_DEFINES
 #include <string>
 #include <vector>
 #include <mutex>