diff --git a/Common/Tools/Multiplicity/multCalibrator.cxx b/Common/Tools/Multiplicity/multCalibrator.cxx
index 493a3d5feac..7d3f4e51019 100644
--- a/Common/Tools/Multiplicity/multCalibrator.cxx
+++ b/Common/Tools/Multiplicity/multCalibrator.cxx
@@ -25,6 +25,7 @@
 #include <TH1D.h>
 #include <TH1F.h>
 #include <TList.h>
+#include <TMath.h>
 #include <TProfile.h>
 #include <TStopwatch.h>