diff --git a/lib/Slic3r/ExtrusionPath/Arc.pm b/lib/Slic3r/ExtrusionPath/Arc.pm
index 59c65c75c..05596f185 100644
--- a/lib/Slic3r/ExtrusionPath/Arc.pm
+++ b/lib/Slic3r/ExtrusionPath/Arc.pm
@@ -17,7 +17,11 @@ sub angle {
 sub length {
     my $self = shift;
     
-    return $self->radius * $self->angle;
+    if($self->orientation eq 'ccw') {
+        return $self->radius * $self->angle;
+    } else {
+        return $self->radius * (2*PI() - $self->angle);
+    }
 }
 
 1;
diff --git a/t/arcs.t b/t/arcs.t
index 7fcc69bf4..981d35e3e 100644
--- a/t/arcs.t
+++ b/t/arcs.t
@@ -2,7 +2,7 @@ use Test::More;
 use strict;
 use warnings;
 
-plan tests => 10;
+plan tests => 12;
 
 BEGIN {
     use FindBin;
@@ -50,7 +50,10 @@ use Slic3r;
     
     isa_ok $collection1->paths->[0], 'Slic3r::ExtrusionPath::Arc', 'path';
     isa_ok $collection2->paths->[0], 'Slic3r::ExtrusionPath::Arc', 'path';
-    
+
+    is $collection1->paths->[0]->length, 7.06858347057701, 'cw oriented arc has correct length';
+    is $collection2->paths->[0]->length, 7.06858347057705, 'ccw oriented arc has correct length';
+
     is $collection1->paths->[0]->orientation, 'cw', 'cw orientation was correctly detected';
     is $collection2->paths->[0]->orientation, 'ccw', 'ccw orientation was correctly detected';