diff --git a/app/bot.php b/app/bot.php
index eb30db9..0b88294 100644
--- a/app/bot.php
+++ b/app/bot.php
@@ -135,6 +135,9 @@ class Bot
             case preg_match('~^/changeAllowedIps (?P<arg>\d+(?:_(?:-)?\d+)?)$~', $this->input['callback'], $m):
                 $this->changeAllowedIps(...explode('_', $m['arg']));
                 break;
+            case preg_match('~^/calc (?P<arg>\d+(?:_(?:-)?\d+)?)$~', $this->input['callback'], $m):
+                $this->calc(...explode('_', $m['arg']));
+                break;
             case preg_match('~^/changeIps (?P<arg>\w+(?:_(?:-)?\d+)?)$~', $this->input['callback'], $m):
                 $this->changeIps(...explode('_', $m['arg']));
                 break;
@@ -1497,9 +1500,68 @@ DNS-over-HTTPS with IP:
         $this->subnet($page);
     }
 
+    public function calc($page)
+    {
+        $r = $this->send(
+            $this->input['chat'],
+            "@{$this->input['username']} enter like '10.0.0.0/24, -10.0.0.5/32'",
+            $this->input['message_id'],
+            reply: 'enter like \'10.0.0.0/24, -10.0.0.5/32\'',
+        );
+        $_SESSION['reply'][$r['result']['message_id']] = [
+            'start_message'  => $this->input['message_id'],
+            'start_callback' => $this->input['callback_id'],
+            'callback'       => 'calcSubnet',
+            'args'           => [$page],
+        ];
+    }
+
+    public function calcSubnet($text)
+    {
+        $text = explode(',', $text);
+        $text = array_map(fn ($e) => trim($e), $text);
+        if (!empty($text)) {
+            foreach ($text as $k => $v) {
+                if (preg_match('~^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}/\d{1,2}~', $v)) {
+                    $include[] = $v;
+                }
+                if (preg_match('~^-(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}/\d{1,2})~', $v, $m)) {
+                    $exclude[] = $m[1];
+                }
+            }
+        }
+        if (!empty($include)) {
+            foreach ($include as $k => $v) {
+                $t = explode('/', $v);
+                $include[$k] = [ip2long($t[0]), ip2long($t[0]) + (1 << (32 - $t[1])) - 1];
+            }
+            if (!empty($exclude)) {
+                foreach ($exclude as $k => $v) {
+                    $t = explode('/', $v);
+                    $exclude[$k] = [ip2long($t[0]), ip2long($t[0]) + (1 << (32 - $t[1])) - 1];
+                }
+            }
+            $c = new Calc();
+            $r = $c->prepare($include, $exclude ?: []);
+            if (!empty($r)) {
+                $t = [];
+                foreach ($r as $k => $v) {
+                    $t = array_merge($t, $c->toCIDR($v[0], $v[1]));
+                }
+                $this->send($this->input['chat'], '<pre>' . implode(', ', $t) . '</pre>');
+            }
+        }
+    }
+
     public function subnet($page = 0, $count = 5)
     {
         $text = "Menu -> Wireguard -> " . $this->i18n('listSubnet') . "\n";
+        $data[] = [
+            [
+                'text'          => $this->i18n('calc'),
+                'callback_data' => "/calc $page",
+            ],
+        ];
         $data[] = [
             [
                 'text'          => $this->i18n('add'),
diff --git a/app/calc.php b/app/calc.php
new file mode 100644
index 0000000..1775812
--- /dev/null
+++ b/app/calc.php
@@ -0,0 +1,79 @@
+<?php
+
+class Calc
+{
+    public function merge(array $a, array $b): array
+    {
+        if ($b[0] > $a[1] + 1) {
+            $tmp = [$a, $b];
+        } elseif ($b[1] <= $a[1]) {
+            $tmp = [$a];
+        } else {
+            $tmp = [[$a[0], $b[1]]];
+        }
+        return array_filter($tmp);
+    }
+
+    public function substract(array $a, array $b): array
+    {
+        if ($b[0] > $a[1] || $b[1] < $a[0]) {
+            return [$a];
+        } elseif ($b[0] <= $a[0] && $b[1] >= $a[1]) {
+            return [];
+        } elseif ($b[0] > $a[0] && $b[1] < $a[1]) {
+            return [[$a[0], $b[0] - 1], [$b[1] + 1, $a[1]]];
+        } elseif ($b[0] <= $a[0]) {
+            return [$b[1] + 1, $a[1]];
+        } else {
+            return [$a[0], $b[1] - 1];
+        }
+    }
+
+    public function alignment(array $arr): array
+    {
+        usort($arr, fn ($a, $b) => $a[0] <=> $b[0]);
+        $tmp = [[]];
+        foreach ($arr as $k => $v) {
+            $t   = array_pop($tmp);
+            $tmp = array_merge($tmp, $this->merge($t, $v));
+        }
+        return $tmp;
+    }
+
+    public function prepare(array $include, array $exclude): array
+    {
+        $include = $this->alignment($include);
+        if (!empty($exclude)) {
+            $tmp = [];
+            $exclude = $this->alignment($exclude);
+            foreach ($exclude as $k => $v) {
+                foreach ($include as $i => $j) {
+                    $tmp = array_merge($tmp, $this->substract($j, $v));
+                }
+                $d = array_filter($tmp);
+            }
+            return $tmp;
+        }
+        return $include;
+    }
+
+    public function toCIDR(int $a, int $b)
+    {
+        $diff = $b - $a + 1;
+        if ($diff > 1) {
+            for ($i = 0; $i <= 32; $i++) {
+                if ($diff / (1 << $i) < 1) {
+                    break;
+                }
+            }
+            $tmp[] = long2ip($a) . "/" . (32 - $i + 1);
+            $new = $a + (1 << ($i - 1));
+            if ($new <= $b) {
+                $tmp = array_merge($tmp, $this->toCIDR($new, $b));
+            }
+        } else {
+            $tmp[] = long2ip($a) . "/32";
+        }
+        return $tmp;
+    }
+}
diff --git a/app/i18n.php b/app/i18n.php
index 93dd3c4..776d26c 100644
--- a/app/i18n.php
+++ b/app/i18n.php
@@ -217,4 +217,8 @@ $i = [
         'en' => 'AllowedIPs',
         'ru' => 'AllowedIPs',
     ],
+    'calc'  => [
+        'en' => 'calc CIDR',
+        'ru' => 'calc CIDR',
+    ],
 ];
diff --git a/app/index.php b/app/index.php
index b071670..51e85b4 100644
--- a/app/index.php
+++ b/app/index.php
@@ -6,6 +6,7 @@ require __DIR__ . '/timezone.php';
 require __DIR__ . '/config.php';
 if ('POST' == $_SERVER['REQUEST_METHOD'] && $_GET['k'] == $c['key']) {
     // require __DIR__ . '/debug.php';
+    require __DIR__ . '/calc.php';
     require __DIR__ . '/bot.php';
     require __DIR__ . '/i18n.php';
     $bot = new Bot($c['key'], $i);