diff --git a/wsprnet.cpp b/wsprnet.cpp
index 942dc0f70..0baba5b93 100644
--- a/wsprnet.cpp
+++ b/wsprnet.cpp
@@ -4,6 +4,8 @@
 
 #include "wsprnet.h"
 
+#include <cmath>
+
 #include <QTimer>
 #include <QFile>
 #include <QNetworkAccessManager>