diff --git a/IP.pm b/IP.pm
index fac167f..5572b51 100644
--- a/IP.pm
+++ b/IP.pm
@@ -32,7 +32,7 @@
 );
 require Exporter;
 
-@EXPORT_OK = qw(Compact Coalesce Zero Zeros Ones V4mask V4net netlimit);
+@EXPORT_OK = qw(Compact Coalesce Zero Zeros Ones V4mask V4net Subtract Exclude netlimit);
 @EXPORT_FAIL = qw($_netlimit);
 
 @ISA = qw(Exporter NetAddr::IP::Lite);
@@ -58,6 +58,8 @@
 	Ones
 	V4mask
 	V4net
+	Subtract
+	Exclude
 	netlimit
 	:aton		DEPRECATED
 	:lower
@@ -421,6 +423,69 @@
   return &coalesce;
 }
 
+=head2 Subtract
+
+ Title    : Subtract
+ Usage    : my $remaining_networks = Subtract(\@list_of_networks,\@networks_to_subtract);
+ Function : computes the network definitions resulting from subtracting @networks_to_subtract from @list_of_networks
+ Returns  : reference to a sorted list of NetAddr::IP objects representing the remaining networks
+ Args     : reference to a sorted list of NetAddr::IP objects (the list must be sorted! eg. by using Compact)
+          : reference to a sorted list of NetAddr::IP objects to subtract (the list must be sorted! eg. by using Compact)
+
+=cut
+sub Subtract {
+  my @add = ref $_[0] eq __PACKAGE__ ? ($_[0]) : @{$_[0]};
+  my @sub = @{$_[1]};
+  my @ret;
+  while (@add && @sub) {
+    if ($add[0]->within($sub[0])) {
+      shift @add;
+    } elsif ($sub[0]->within($add[0])) {
+      my ($low,$up) = Exclude(shift @add,shift @sub);
+      push @ret, @$low;
+      unshift @add, @$up;
+    } else {
+      if ($add[0]->bigint < $sub[0]->bigint) {
+        push @ret, shift @add;
+      } else {
+        shift @sub;
+      }
+    }
+  }
+  push @ret, @add;
+  return \@ret;
+}
+
+=head2 Exclude
+
+ Title    : Exclude
+ Usage    : my ($remaining_lower_networks,$remaining_upper_networks) = Exclude($original_network,$network_to_exclude);
+ Function : computes the network definitions resulting from removing the $network_to_exclude from $original_network.
+ Returns  : two list references containing the sorted network definitions 'below' and 'above' the excluded network
+ Args     : NetAddr::IP object of the original network
+          : NetAddr::IP object of the network to exclude
+
+=cut
+sub Exclude {
+  return ([],[]) if $_[0] == $_[1];
+  return ([$_[0]],[]) unless $_[1]->within($_[0]);
+  my @low;
+  my @up;
+  my ($s1,$s2) = $_[0]->split($_[0]->masklen+1);
+  while ($s1 != $_[1] && $s2 != $_[1]) {
+    if ($_[1]->within($s1)) {
+      unshift @up, $s2;
+      ($s1,$s2) = $s1->split($s1->masklen+1);
+    } else {
+      push @low, $s1;
+      ($s1,$s2) = $s2->split($s2->masklen+1);
+    }
+  }
+  push @low, $s1 if $s2 == $_[1];
+  unshift @up, $s2 if $s1 == $_[1];
+  return (\@low,\@up);
+}
+
 sub hostenumref($) {
   my $r = _splitref(0,$_[0]);
   unless ((notcontiguous($_[0]->{mask}))[1] == 128 ||
diff --git a/t/v4-exclude.t b/t/v4-exclude.t
new file mode 100644
index 0000000..101e5a2
--- /dev/null
+++ b/t/v4-exclude.t
@@ -0,0 +1,31 @@
+use Test::More;
+use NetAddr::IP qw(Exclude);
+
+my @r = (
+	['10.0.0.0/8','10.0.0.0/9', [], ['10.128.0.0/9']],
+	['10.0.0.0/8','10.0.0.0/8', [], []],
+	['10.0.0.0/8','10.128.0.0/9', ['10.0.0.0/9'], []],
+	['10.0.0.0/8','10.128.0.0/10', ['10.0.0.0/9'], ['10.192.0.0/10']],
+	['10.0.0.0/8','10.0.0.0/32', [], ['10.0.0.1/32','10.0.0.2/31','10.0.0.4/30','10.0.0.8/29','10.0.0.16/28','10.0.0.32/27','10.0.0.64/26','10.0.0.128/25','10.0.1.0/24','10.0.2.0/23','10.0.4.0/22','10.0.8.0/21','10.0.16.0/20','10.0.32.0/19','10.0.64.0/18','10.0.128.0/17','10.1.0.0/16','10.2.0.0/15','10.4.0.0/14','10.8.0.0/13','10.16.0.0/12','10.32.0.0/11','10.64.0.0/10','10.128.0.0/9']],
+	['192.168.0.0/24','192.168.0.255/32',['192.168.0.0/25','192.168.0.128/26','192.168.0.192/27','192.168.0.224/28','192.168.0.240/29','192.168.0.248/30','192.168.0.252/31','192.168.0.254/32'],[]],
+	['192.168.0.0/23','192.168.0.127/32',['192.168.0.0/26','192.168.0.64/27','192.168.0.96/28','192.168.0.112/29','192.168.0.120/30','192.168.0.124/31','192.168.0.126/32'],['192.168.0.128/25','192.168.1.0/24']],
+	['1.2.3.4/32','1.2.3.4/32',[],[]],
+	['0.0.0.0/0','0.0.0.0/32',[],['0.0.0.1/32','0.0.0.2/31','0.0.0.4/30','0.0.0.8/29','0.0.0.16/28','0.0.0.32/27','0.0.0.64/26','0.0.0.128/25','0.0.1.0/24','0.0.2.0/23','0.0.4.0/22','0.0.8.0/21','0.0.16.0/20','0.0.32.0/19','0.0.64.0/18','0.0.128.0/17','0.1.0.0/16','0.2.0.0/15','0.4.0.0/14','0.8.0.0/13','0.16.0.0/12','0.32.0.0/11','0.64.0.0/10','0.128.0.0/9','1.0.0.0/8','2.0.0.0/7','4.0.0.0/6','8.0.0.0/5','16.0.0.0/4','32.0.0.0/3','64.0.0.0/2','128.0.0.0/1']],
+	['1.2.3.4/32','1.2.3.5/32',['1.2.3.4/32'],[]],
+);
+
+plan tests => 4 * scalar @r;
+
+SKIP: {
+	foreach my $case (@r) {
+		my ($low, $up) = Exclude(NetAddr::IP->new($case->[0]), NetAddr::IP->new($case->[1]));
+		my $ex_low = [map { NetAddr::IP->new($_) } @{$case->[2]}];
+		my $ex_up = [map { NetAddr::IP->new($_) } @{$case->[3]}];
+		is("@$up", "@$ex_up", "Upper half of Exclude($case->[0],$case->[1]) is @$ex_up");
+		is("@$low", "@$ex_low", "Lower half of Exclude($case->[0],$case->[1]) is @$ex_low");
+
+		($low, $up) = NetAddr::IP->new($case->[0])->Exclude(NetAddr::IP->new($case->[1]));
+		is("@$up", "@$ex_up", "Upper half of ($case->[0])->Exclude($case->[1]) is @$ex_up");
+		is("@$low", "@$ex_low", "Lower half of ($case->[0])->Exclude($case->[1]) is @$ex_low");
+	}
+}
diff --git a/t/v4-subtract.t b/t/v4-subtract.t
new file mode 100644
index 0000000..113934c
--- /dev/null
+++ b/t/v4-subtract.t
@@ -0,0 +1,86 @@
+use Test::More;
+use NetAddr::IP qw(Exclude Subtract);
+
+my @r = (
+	['10.0.0.0/8','10.0.0.0/9'],
+	['10.0.0.0/8','10.0.0.0/8'],
+	['10.0.0.0/8','10.128.0.0/9'],
+	['10.0.0.0/8','10.128.0.0/10'],
+	['10.0.0.0/8','10.0.0.0/32'],
+	['192.168.0.0/24','192.168.0.255/32'],
+	['192.168.0.0/23','192.168.0.127/32'],
+	['1.2.3.4/32','1.2.3.4/32'],
+	['0.0.0.0/0','0.0.0.0/32'],
+);
+
+plan tests => 1 + 19 * scalar @r;
+
+SKIP: {
+	my $res = Subtract([],[]);
+	is("@$res", "", "Subtract([],[]) returns an empty list");
+
+	foreach my $case (@r) {
+		my $whole = [NetAddr::IP->new($case->[0])];
+		my $part1 = [NetAddr::IP->new($case->[1])];
+		my ($low,$up) = Exclude($whole->[0],$part1->[0]);
+		my $part2 = [@{$low},@{$up}];
+		my $res = [];
+
+		$res = Subtract($whole,$part1);
+		is("@$res", "@$part2", "Subtract(@$whole,@$part1) returns @$part2");
+
+		$res = $whole->[0]->Subtract($part1);
+		is("@$res", "@$part2", "($whole->[0])->Subtract(@$part1) returns @$part2");
+
+		$res = Subtract($whole,$part2);
+		is("@$res", "@$part1", "Subtract(@$whole,@$part2) returns @$part1");
+
+		$res = $whole->[0]->Subtract($part2);
+		is("@$res", "@$part1", "($whole->[0])->Subtract(@$part2) returns @$part1");
+
+		$res = Subtract($part1,$part2);
+		is("@$res", "@$part1", "Subtract(@$part1,@$part2) returns @$part1");
+
+		$res = $part1->[0]->Subtract($part2);
+		is("@$res", "@$part1", "($part1->[0])->Subtract(@$part2) returns @$part1");
+
+		$res = Subtract($part2,$part1);
+		is("@$res", "@$part2", "Subtract(@$part2,@$part1) returns @$part2");
+
+		$res = Subtract(Subtract($whole,$part1),$part2);
+		is("@$res", "", "Subtract(Subtract(@$whole,@$part1),$part2) returns an empty list");
+
+		$res = Subtract($whole->[0]->Subtract($part1),$part2);
+		is("@$res", "", "Subtract(($whole->[0])->Subtract(@$part1),$part2) returns an empty list");
+
+		$res = Subtract(Subtract($whole,$part2),$part1);
+		is("@$res", "", "Subtract(Subtract(@$whole,@$part2),$part1) returns an empty list");
+
+		$res = Subtract($whole->[0]->Subtract($part2),$part1);
+		is("@$res", "", "Subtract(($whole->[0])->Subtract(@$part2),$part1) returns an empty list");
+
+		$res = Subtract($whole,$whole);
+		is("@$res", "", "Subtract(@$whole,@$whole) returns an empty list");
+
+		$res = $whole->[0]->Subtract($whole);
+		is("@$res", "", "($whole->[0])->Subtract(@$whole) returns an empty list");
+
+		$res = Subtract($part1,$part1);
+		is("@$res", "", "Subtract(@$part1,@$part1) returns an empty list");
+
+		$res = $part1->[0]->Subtract($part1);
+		is("@$res", "", "($part1->[0])->Subract(@$part1) returns an empty list");
+
+		$res = Subtract($part2,$part2);
+		is("@$res", "", "Subtract(@$part2,@$part2) returns an empty list");
+
+		$res = Subtract($part1,$whole);
+		is("@$res", "", "Subtract(@$part1,@$whole) returns an empty list");
+
+		$res = $part1->[0]->Subtract($whole);
+		is("@$res", "", "($part1->[0])->Subtract(@$whole) returns an empty list");
+
+		$res = Subtract($part2,$whole);
+		is("@$res", "", "Subtract(@$part2,@$whole) returns an empty list");
+	}
+}
diff --git a/t/v6-exclude.t b/t/v6-exclude.t
new file mode 100644
index 0000000..53aadd6
--- /dev/null
+++ b/t/v6-exclude.t
@@ -0,0 +1,28 @@
+use Test::More;
+use NetAddr::IP qw(:lower Exclude);
+
+my @r = (
+	['2001:db8::/32','2001:db8::/33', [], ['2001:db8:8000::/33']],
+	['2001:db8::/64','2001:db8::/64', [], []],
+	['2001:db8::/128','2001:db8::/128', [], []],
+	['2001:db8::/32','2001:db8:8000::/33', ['2001:db8::/33'], []],
+	['2001:db8::/32','2001:db8:8000::/34', ['2001:db8::/33'], ['2001:db8:c000::/34']],
+	['::/0','::/128', [], ['0:0:0:0:0:0:0:1/128','0:0:0:0:0:0:0:2/127','0:0:0:0:0:0:0:4/126','0:0:0:0:0:0:0:8/125','0:0:0:0:0:0:0:10/124','0:0:0:0:0:0:0:20/123','0:0:0:0:0:0:0:40/122','0:0:0:0:0:0:0:80/121','0:0:0:0:0:0:0:100/120','0:0:0:0:0:0:0:200/119','0:0:0:0:0:0:0:400/118','0:0:0:0:0:0:0:800/117','0:0:0:0:0:0:0:1000/116','0:0:0:0:0:0:0:2000/115','0:0:0:0:0:0:0:4000/114','0:0:0:0:0:0:0:8000/113','0:0:0:0:0:0:1:0/112','0:0:0:0:0:0:2:0/111','0:0:0:0:0:0:4:0/110','0:0:0:0:0:0:8:0/109','0:0:0:0:0:0:10:0/108','0:0:0:0:0:0:20:0/107','0:0:0:0:0:0:40:0/106','0:0:0:0:0:0:80:0/105','0:0:0:0:0:0:100:0/104','0:0:0:0:0:0:200:0/103','0:0:0:0:0:0:400:0/102','0:0:0:0:0:0:800:0/101','0:0:0:0:0:0:1000:0/100','0:0:0:0:0:0:2000:0/99','0:0:0:0:0:0:4000:0/98','0:0:0:0:0:0:8000:0/97','0:0:0:0:0:1:0:0/96','0:0:0:0:0:2:0:0/95','0:0:0:0:0:4:0:0/94','0:0:0:0:0:8:0:0/93','0:0:0:0:0:10:0:0/92','0:0:0:0:0:20:0:0/91','0:0:0:0:0:40:0:0/90','0:0:0:0:0:80:0:0/89','0:0:0:0:0:100:0:0/88','0:0:0:0:0:200:0:0/87','0:0:0:0:0:400:0:0/86','0:0:0:0:0:800:0:0/85','0:0:0:0:0:1000:0:0/84','0:0:0:0:0:2000:0:0/83','0:0:0:0:0:4000:0:0/82','0:0:0:0:0:8000:0:0/81','0:0:0:0:1:0:0:0/80','0:0:0:0:2:0:0:0/79','0:0:0:0:4:0:0:0/78','0:0:0:0:8:0:0:0/77','0:0:0:0:10:0:0:0/76','0:0:0:0:20:0:0:0/75','0:0:0:0:40:0:0:0/74','0:0:0:0:80:0:0:0/73','0:0:0:0:100:0:0:0/72','0:0:0:0:200:0:0:0/71','0:0:0:0:400:0:0:0/70','0:0:0:0:800:0:0:0/69','0:0:0:0:1000:0:0:0/68','0:0:0:0:2000:0:0:0/67','0:0:0:0:4000:0:0:0/66','0:0:0:0:8000:0:0:0/65','0:0:0:1:0:0:0:0/64','0:0:0:2:0:0:0:0/63','0:0:0:4:0:0:0:0/62','0:0:0:8:0:0:0:0/61','0:0:0:10:0:0:0:0/60','0:0:0:20:0:0:0:0/59','0:0:0:40:0:0:0:0/58','0:0:0:80:0:0:0:0/57','0:0:0:100:0:0:0:0/56','0:0:0:200:0:0:0:0/55','0:0:0:400:0:0:0:0/54','0:0:0:800:0:0:0:0/53','0:0:0:1000:0:0:0:0/52','0:0:0:2000:0:0:0:0/51','0:0:0:4000:0:0:0:0/50','0:0:0:8000:0:0:0:0/49','0:0:1:0:0:0:0:0/48','0:0:2:0:0:0:0:0/47','0:0:4:0:0:0:0:0/46','0:0:8:0:0:0:0:0/45','0:0:10:0:0:0:0:0/44','0:0:20:0:0:0:0:0/43','0:0:40:0:0:0:0:0/42','0:0:80:0:0:0:0:0/41','0:0:100:0:0:0:0:0/40','0:0:200:0:0:0:0:0/39','0:0:400:0:0:0:0:0/38','0:0:800:0:0:0:0:0/37','0:0:1000:0:0:0:0:0/36','0:0:2000:0:0:0:0:0/35','0:0:4000:0:0:0:0:0/34','0:0:8000:0:0:0:0:0/33','0:1:0:0:0:0:0:0/32','0:2:0:0:0:0:0:0/31','0:4:0:0:0:0:0:0/30','0:8:0:0:0:0:0:0/29','0:10:0:0:0:0:0:0/28','0:20:0:0:0:0:0:0/27','0:40:0:0:0:0:0:0/26','0:80:0:0:0:0:0:0/25','0:100:0:0:0:0:0:0/24','0:200:0:0:0:0:0:0/23','0:400:0:0:0:0:0:0/22','0:800:0:0:0:0:0:0/21','0:1000:0:0:0:0:0:0/20','0:2000:0:0:0:0:0:0/19','0:4000:0:0:0:0:0:0/18','0:8000:0:0:0:0:0:0/17','1:0:0:0:0:0:0:0/16','2:0:0:0:0:0:0:0/15','4:0:0:0:0:0:0:0/14','8:0:0:0:0:0:0:0/13','10:0:0:0:0:0:0:0/12','20:0:0:0:0:0:0:0/11','40:0:0:0:0:0:0:0/10','80:0:0:0:0:0:0:0/9','100:0:0:0:0:0:0:0/8','200:0:0:0:0:0:0:0/7','400:0:0:0:0:0:0:0/6','800:0:0:0:0:0:0:0/5','1000:0:0:0:0:0:0:0/4','2000:0:0:0:0:0:0:0/3','4000:0:0:0:0:0:0:0/2','8000:0:0:0:0:0:0:0/1']],
+	['2001:db8::/128','2001:db8:1::/128', ['2001:db8::/128'], []],
+);
+
+plan tests => 4 * scalar @r;
+
+SKIP: {
+	foreach my $case (@r) {
+		my ($low, $up) = Exclude(NetAddr::IP->new($case->[0]), NetAddr::IP->new($case->[1]));
+		my $ex_low = [map { NetAddr::IP->new($_) } @{$case->[2]}];
+		my $ex_up = [map { NetAddr::IP->new($_) } @{$case->[3]}];
+		is("@$up", "@$ex_up", "Upper half of Exclude($case->[0],$case->[1]) is @$ex_up");
+		is("@$low", "@$ex_low", "Lower half of Exclude($case->[0],$case->[1]) is @$ex_low");
+
+		($low, $up) = NetAddr::IP->new($case->[0])->Exclude(NetAddr::IP->new($case->[1]));
+		is("@$up", "@$ex_up", "Upper half of ($case->[0])->Exclude($case->[1]) is @$ex_up");
+		is("@$low", "@$ex_low", "Lower half of ($case->[0])->Exclude($case->[1]) is @$ex_low");
+	}
+}
diff --git a/t/v6-subtract.t b/t/v6-subtract.t
new file mode 100644
index 0000000..9274688
--- /dev/null
+++ b/t/v6-subtract.t
@@ -0,0 +1,82 @@
+use Test::More;
+use NetAddr::IP qw(:lower Exclude Subtract);
+
+my @r = (
+	['2001:db8::/32','2001:db8::/33'],
+	['2001:db8::/64','2001:db8::/64'],
+	['2001:db8::/128','2001:db8::/128'],
+	['2001:db8::/32','2001:db8:8000::/33'],
+	['2001:db8::/32','2001:db8:8000::/34'],
+);
+
+plan tests => 1 + 19 * scalar @r;
+
+SKIP: {
+	my $res = Subtract([],[]);
+	is("@$res", "", "Subtract([],[]) returns an empty list");
+
+	foreach my $case (@r) {
+		my $whole = [NetAddr::IP->new($case->[0])];
+		my $part1 = [NetAddr::IP->new($case->[1])];
+		my ($low,$up) = Exclude($whole->[0],$part1->[0]);
+		my $part2 = [@{$low},@{$up}];
+		my $res = [];
+
+		$res = Subtract($whole,$part1);
+		is("@$res", "@$part2", "Subtract(@$whole,@$part1) returns @$part2");
+
+		$res = $whole->[0]->Subtract($part1);
+		is("@$res", "@$part2", "($whole->[0])->Subtract(@$part1) returns @$part2");
+
+		$res = Subtract($whole,$part2);
+		is("@$res", "@$part1", "Subtract(@$whole,@$part2) returns @$part1");
+
+		$res = $whole->[0]->Subtract($part2);
+		is("@$res", "@$part1", "($whole->[0])->Subtract(@$part2) returns @$part1");
+
+		$res = Subtract($part1,$part2);
+		is("@$res", "@$part1", "Subtract(@$part1,@$part2) returns @$part1");
+
+		$res = $part1->[0]->Subtract($part2);
+		is("@$res", "@$part1", "($part1->[0])->Subtract(@$part2) returns @$part1");
+
+		$res = Subtract($part2,$part1);
+		is("@$res", "@$part2", "Subtract(@$part2,@$part1) returns @$part2");
+
+		$res = Subtract(Subtract($whole,$part1),$part2);
+		is("@$res", "", "Subtract(Subtract(@$whole,@$part1),$part2) returns an empty list");
+
+		$res = Subtract($whole->[0]->Subtract($part1),$part2);
+		is("@$res", "", "Subtract(($whole->[0])->Subtract(@$part1),$part2) returns an empty list");
+
+		$res = Subtract(Subtract($whole,$part2),$part1);
+		is("@$res", "", "Subtract(Subtract(@$whole,@$part2),$part1) returns an empty list");
+
+		$res = Subtract($whole->[0]->Subtract($part2),$part1);
+		is("@$res", "", "Subtract(($whole->[0])->Subtract(@$part2),$part1) returns an empty list");
+
+		$res = Subtract($whole,$whole);
+		is("@$res", "", "Subtract(@$whole,@$whole) returns an empty list");
+
+		$res = $whole->[0]->Subtract($whole);
+		is("@$res", "", "($whole->[0])->Subtract(@$whole) returns an empty list");
+
+		$res = Subtract($part1,$part1);
+		is("@$res", "", "Subtract(@$part1,@$part1) returns an empty list");
+
+		$res = $part1->[0]->Subtract($part1);
+		is("@$res", "", "($part1->[0])->Subract(@$part1) returns an empty list");
+
+		$res = Subtract($part2,$part2);
+		is("@$res", "", "Subtract(@$part2,@$part2) returns an empty list");
+
+		$res = Subtract($part1,$whole);
+		is("@$res", "", "Subtract(@$part1,@$whole) returns an empty list");
+
+		$res = $part1->[0]->Subtract($whole);
+		is("@$res", "", "($part1->[0])->Subtract(@$whole) returns an empty list");
+
+		$res = Subtract($part2,$whole);
+		is("@$res", "", "Subtract(@$part2,@$whole) returns an empty list");
+	}
+}