diff --git a/include/gestures/include/finger_metrics.h b/include/gestures/include/finger_metrics.h
index 5440e19..9ae2910 100644
--- a/include/gestures/include/finger_metrics.h
+++ b/include/gestures/include/finger_metrics.h
@@ -5,6 +5,7 @@
 #ifndef GESTURES_FINGER_METRICS_H_
 #define GESTURES_FINGER_METRICS_H_
 
+#include <math.h>
 #include "gestures/include/gestures.h"
 #include "gestures/include/prop_registry.h"
 #include "gestures/include/vector.h"