diff --git a/lib/Slic3r/Extruder.pm b/lib/Slic3r/Extruder.pm
index 4c88b97b89..9711e0c3c1 100644
--- a/lib/Slic3r/Extruder.pm
+++ b/lib/Slic3r/Extruder.pm
@@ -128,7 +128,7 @@ sub extrude_path {
     
     # calculate extrusion length per distance unit
     my $s = $path->flow_spacing || $Slic3r::flow_spacing;
-    my $h = $path->depth_layers * $Slic3r::layer_height;
+    my $h = $path->depth_layers * $self->layer->height;
     my $w = ($s - $Slic3r::min_flow_spacing * $Slic3r::overlap_factor) / (1 - $Slic3r::overlap_factor);
     
     my $area;
diff --git a/lib/Slic3r/Layer.pm b/lib/Slic3r/Layer.pm
index d03365b76d..9b6fb56040 100644
--- a/lib/Slic3r/Layer.pm
+++ b/lib/Slic3r/Layer.pm
@@ -91,6 +91,13 @@ sub print_z {
         + ($self->id * $Slic3r::layer_height)) / $Slic3r::resolution;
 }
 
+sub height {
+    my $self = shift;
+    return $self->id == 0
+        ? ($Slic3r::layer_height * $Slic3r::first_layer_height_ratio)
+        : $Slic3r::layer_height;
+}
+
 sub add_line {
     my $self = shift;
     my ($line) = @_;