diff --git a/src/laser_geometry.cpp b/src/laser_geometry.cpp
index 2e2befe..ea27fd6 100644
--- a/src/laser_geometry.cpp
+++ b/src/laser_geometry.cpp
@@ -214,7 +214,7 @@ const boost::numeric::ublas::matrix<double>& LaserProjection::getUnitVectors_(do
 
     // Extract transforms for the beginning and end of the laser scan
     ros::Time start_time = scan_in.header.stamp ;
-    ros::Time end_time   = scan_in.header.stamp + ros::Duration().fromSec(scan_in.ranges.size()*scan_in.time_increment) ;
+    ros::Time end_time   = scan_in.header.stamp + ros::Duration().fromSec( (scan_in.ranges.size()-1) * scan_in.time_increment);
 
     tf::StampedTransform start_transform ;
     tf::StampedTransform end_transform ;
@@ -550,7 +550,7 @@ const boost::numeric::ublas::matrix<double>& LaserProjection::getUnitVectors_(do
 
     // Extract transforms for the beginning and end of the laser scan
     ros::Time start_time = scan_in.header.stamp;
-    ros::Time end_time   = scan_in.header.stamp + ros::Duration ().fromSec (scan_in.ranges.size () * scan_in.time_increment);
+    ros::Time end_time   = scan_in.header.stamp + ros::Duration ().fromSec ( (scan_in.ranges.size()-1) * scan_in.time_increment);
 
     tf::StampedTransform start_transform, end_transform, cur_transform ;