diff --git a/src/caffe/util/bbox_util.cpp b/src/caffe/util/bbox_util.cpp
index 82159df3..ef3dcf30 100644
--- a/src/caffe/util/bbox_util.cpp
+++ b/src/caffe/util/bbox_util.cpp
@@ -1137,7 +1137,8 @@ void VisualizeBBox(const vector<cv::Mat>& images, const Blob<Dtype>* detections,
     return;
   }
   // Comute FPS.
-  float fps = num_img / (double(clock() - start_clock) / CLOCKS_PER_SEC);
+  float fps = num_img / (static_cast<double>(clock() - start_clock) /
+          CLOCKS_PER_SEC);
   start_clock = clock();
 
   const Dtype* detections_data = detections->cpu_data();