diff --git a/source/Math/Logarithm.cpp b/source/Math/Logarithm.cpp
index 4fe83eb..2d6c6ad 100644
--- a/source/Math/Logarithm.cpp
+++ b/source/Math/Logarithm.cpp
@@ -1,6 +1,6 @@
 
 // Logarithmic functions.
-#include <cstdlib>
+#include <cmath>
 #include <Spectre/Math/Math.h>
 
 namespace sp {