diff --git a/include/mason/methylation_levels.h b/include/mason/methylation_levels.h
index 3595ad6..fbbaf06 100644
--- a/include/mason/methylation_levels.h
+++ b/include/mason/methylation_levels.h
@@ -35,6 +35,8 @@
 #ifndef APPS_MASON2_METHYLATION_LEVELS_H_
 #define APPS_MASON2_METHYLATION_LEVELS_H_
 
+#include <cmath>
+#include <cstdlib>
 #include <seqan/index.h>  // for Shape<>
 #include <seqan/sequence.h>
 #include <seqan/sequence_journaled.h>  // for the journal