diff --git a/lib/nBodySim.hpp b/lib/nBodySim.hpp
index 31c80168ce90c56a08c2fa8e7a7110a221440bf8..c6fc75c23e3f72cf277ec04b722df66e1b34e06c 100644
--- a/lib/nBodySim.hpp
+++ b/lib/nBodySim.hpp
@@ -1,5 +1,5 @@
-#ifndef NBODYSIM_H
-#define NBODYSIM_H
+#ifndef NBODYSIM_HPP
+#define NBODYSIM_HPP
 
 #include <string>
 
@@ -44,4 +44,4 @@ private:
     double meanForceMagnitude_;
 };
 
-#endif /* NBODYSIM_H */
\ No newline at end of file
+#endif /* NBODYSIM_HPP */
\ No newline at end of file