diff --git a/src/kcf.cpp b/src/kcf.cpp
index 0e358a9c..58fc6f5c 100644
--- a/src/kcf.cpp
+++ b/src/kcf.cpp
@@ -57,8 +57,8 @@ void KCF_Tracker::init(cv::Mat &img, const cv::Rect & bbox)
     }
 
     //compute win size + fit to fhog cell size
-    p_windows_size[0] = round(p_pose.w * (1. + p_padding) / p_cell_size) * p_cell_size;
-    p_windows_size[1] = round(p_pose.h * (1. + p_padding) / p_cell_size) * p_cell_size;
+    p_windows_size[0] = ceil(p_pose.w * (1. + p_padding) / (float)(p_cell_size*2)) * p_cell_size * 2;
+    p_windows_size[1] = ceil(p_pose.h * (1. + p_padding) / (float)(p_cell_size*2)) * p_cell_size * 2;
 
     p_scales.clear();
     if (m_use_scale)
@@ -659,4 +659,4 @@ double KCF_Tracker::sub_grid_scale(std::vector<double> & responses, int index)
     if (a > 0 || a < 0)
         scale = -b / (2 * a);
     return scale;
-}
\ No newline at end of file
+}