diff --git a/src/libslic3r/ExPolygon.cpp b/src/libslic3r/ExPolygon.cpp
index 222cb2440..19ca5a057 100644
--- a/src/libslic3r/ExPolygon.cpp
+++ b/src/libslic3r/ExPolygon.cpp
@@ -9,6 +9,7 @@
 #include <algorithm>
 #include <cassert>
 #include <list>
+#include <numeric>
 
 namespace Slic3r {
 
diff --git a/src/libslic3r/Polygon.cpp b/src/libslic3r/Polygon.cpp
index e256aadee..222ebf3d4 100644
--- a/src/libslic3r/Polygon.cpp
+++ b/src/libslic3r/Polygon.cpp
@@ -4,6 +4,8 @@
 #include "Polygon.hpp"
 #include "Polyline.hpp"
 
+#include <numeric>
+
 namespace Slic3r {
 
 double Polygon::length() const