diff --git a/lib/Slic3r/Print.pm b/lib/Slic3r/Print.pm
index 97eb0a399..1129080d4 100644
--- a/lib/Slic3r/Print.pm
+++ b/lib/Slic3r/Print.pm
@@ -446,7 +446,7 @@ sub export_gcode {
     # write some information
     my @lt = localtime;
     printf $fh "; generated by Slic3r $Slic3r::VERSION on %02d-%02d-%02d at %02d:%02d:%02d\n\n",
-        $lt[5] + 1900, $lt[4], $lt[3], $lt[2], $lt[1], $lt[0];
+        $lt[5] + 1900, $lt[4]+1, $lt[3], $lt[2], $lt[1], $lt[0];
     
     for (qw(layer_height perimeters solid_layers fill_density nozzle_diameter filament_diameter
         perimeter_speed infill_speed travel_speed extrusion_width_ratio scale)) {