diff --git a/scripts/ipcalc b/scripts/ipcalc
index c2f468c..9b211b3 100755
--- a/scripts/ipcalc
+++ b/scripts/ipcalc
@@ -30,6 +30,7 @@
 #
 # ------------------------------------------------------------------------------
 
+package require math::bignum
 
 # Convert integer to binary
 proc int2bin {int} {
@@ -52,6 +53,18 @@ proc decimal2binary {decimal_ip} {
 	return [join [lmap x [split $decimal_ip {.}] {int2bin $x}] {.}]
 }
 
+# Bignum calculation
+proc = {expr x y} {
+	set big_x [::math::bignum::fromstr $x 2]
+
+	pad_address [::math::bignum::tostr [::math::bignum::$expr $big_x $y] 2]
+}
+
+# Add leader zeroes to binary IP address
+proc pad_address {binary_ip} {
+	format %032s $binary_ip
+}
+
 # Normalize binary form of IP address
 # E.g.:
 #   11111111.11111111.11111111.00000000 => 11111111111111111111111100000000
@@ -182,7 +195,8 @@ proc host_broadcast {ip netmask} {
 # 190.0.15.254    10111110.00000000.00001111.11111110
 proc host_max {ip netmask} {
 	set binary_broadcast [lindex [host_broadcast $ip $netmask] 1]
-	set binary_max_host  [format_binary_ip [expr {[normalize_binary_ip [lindex [host_broadcast $ip $netmask] 1]]-1}]]
+	set normalized_binary_ip [normalize_binary_ip [lindex [host_broadcast $ip $netmask] 1]]
+	set binary_max_host [format_binary_ip [pad_address [= sub $normalized_binary_ip 1]]]
 	set max_host [binary2decimal $binary_max_host]
 
 	return [list $max_host $binary_max_host]
@@ -199,7 +213,8 @@ proc host_max {ip netmask} {
 proc host_min {ip netmask} {
 	set network [lindex [network $ip $netmask] 1]
 
-	set min_host [expr {[normalize_binary_ip $network]+1}]
+	set normalized_binary_ip [normalize_binary_ip $network]
+	set min_host [= add $normalized_binary_ip 1]
 	set binary_min_host [format_binary_ip $min_host]
 	set decimal_min_host [binary2decimal $min_host]