diff --git a/data/web/edit.php b/data/web/edit.php
index c44464df..9aa79269 100644
--- a/data/web/edit.php
+++ b/data/web/edit.php
@@ -521,7 +521,8 @@ if (isset($_SESSION['mailcow_cc_role'])) {
               <br /><span id="quotaBadge" class="badge">max. <?=intval($result['max_new_quota'] / 1048576)?> MiB</span>
             </label>
             <div class="col-sm-10">
-              <input type="number" name="quota" style="width:100%" min="1" max="<?=intval($result['max_new_quota'] / 1048576);?>" value="<?=intval($result['quota']) / 1048576;?>" class="form-control">
+              <input type="number" name="quota" style="width:100%" min="0" max="<?=intval($result['max_new_quota'] / 1048576);?>" value="<?=intval($result['quota']) / 1048576;?>" class="form-control">
+              <small class="help-block">0 = ∞</small>
             </div>
           </div>
           <div class="form-group">
diff --git a/data/web/inc/functions.inc.php b/data/web/inc/functions.inc.php
index c869c122..ebce5819 100644
--- a/data/web/inc/functions.inc.php
+++ b/data/web/inc/functions.inc.php
@@ -1,4 +1,12 @@
 <?php
+function isset_has_content($var) {
+  if (isset($var) && $var != "") {
+    return true;
+  }
+  else {
+    return false;
+  }
+}
 function hash_password($password) {
 	$salt_str = bin2hex(openssl_random_pseudo_bytes(8));
 	return "{SSHA256}".base64_encode(hash('sha256', $password . $salt_str, true) . $salt_str);
diff --git a/data/web/inc/functions.mailbox.inc.php b/data/web/inc/functions.mailbox.inc.php
index b9129f83..6ecb3a94 100644
--- a/data/web/inc/functions.mailbox.inc.php
+++ b/data/web/inc/functions.mailbox.inc.php
@@ -756,7 +756,7 @@ function mailbox($_action, $_type, $_data = null, $_extra = null) {
           $password     = $_data['password'];
           $password2    = $_data['password2'];
           $name         = ltrim(rtrim($_data['name'], '>'), '<');
-          $quota_m			= filter_var($_data['quota'], FILTER_SANITIZE_NUMBER_FLOAT);
+          $quota_m			= intval($_data['quota']);
           if (empty($name)) {
             $name = $local_part;
           }
@@ -844,14 +844,6 @@ function mailbox($_action, $_type, $_data = null, $_extra = null) {
             );
             return false;
           }
-          if (!is_numeric($quota_m) || $quota_m == "0") {
-            $_SESSION['return'][] = array(
-              'type' => 'danger',
-              'log' => array(__FUNCTION__, $_action, $_type, $_data_log, $_attr),
-              'msg' => 'quota_not_0_not_numeric'
-            );
-            return false;
-          }
           if (!empty($password) && !empty($password2)) {
             if (!preg_match('/' . $GLOBALS['PASSWD_REGEP'] . '/', $password)) {
               $_SESSION['return'][] = array(
@@ -1993,9 +1985,9 @@ function mailbox($_action, $_type, $_data = null, $_extra = null) {
               $active     = (isset($_data['active'])) ? intval($_data['active']) : $is_now['active_int'];
               (int)$force_pw_update = (isset($_data['force_pw_update'])) ? intval($_data['force_pw_update']) : intval($is_now['attributes']['force_pw_update']);
               (int)$sogo_access = (isset($_data['sogo_access'])) ? intval($_data['sogo_access']) : intval($is_now['attributes']['sogo_access']);
+              (int)$quota_m = (isset_has_content($_data['quota'])) ? intval($_data['quota']) : ($is_now['quota'] / 1048576);
               $name       = (!empty($_data['name'])) ? ltrim(rtrim($_data['name'], '>'), '<') : $is_now['name'];
               $domain     = $is_now['domain'];
-              $quota_m    = (!empty($_data['quota'])) ? $_data['quota'] : ($is_now['quota'] / 1048576);
               $quota_b    = $quota_m * 1048576;
               $password   = (!empty($_data['password'])) ? $_data['password'] : null;
               $password2  = (!empty($_data['password2'])) ? $_data['password2'] : null; 
@@ -2021,14 +2013,6 @@ function mailbox($_action, $_type, $_data = null, $_extra = null) {
               );
               continue;
             }
-            if (!is_numeric($quota_m) || $quota_m == "0") {
-              $_SESSION['return'][] = array(
-                'type' => 'danger',
-                'log' => array(__FUNCTION__, $_action, $_type, $_data_log, $_attr),
-                'msg' => array('quota_not_0_not_numeric', htmlspecialchars($quota_m))
-              );
-              continue;
-            }
             if ($quota_m > $DomainData['maxquota']) {
               $_SESSION['return'][] = array(
                 'type' => 'danger',
@@ -3016,15 +3000,18 @@ function mailbox($_action, $_type, $_data = null, $_extra = null) {
           $mailboxdata['quota'] = $row['quota'];
           $mailboxdata['attributes'] = json_decode($row['attributes'], true);
           $mailboxdata['quota_used'] = intval($row['bytes']);
-          $mailboxdata['percent_in_use'] = round((intval($row['bytes']) / intval($row['quota'])) * 100);
+          $mailboxdata['percent_in_use'] = ($row['quota'] == 0) ? '- ' : round((intval($row['bytes']) / intval($row['quota'])) * 100);
           $mailboxdata['messages'] = $row['messages'];
           $mailboxdata['spam_aliases'] = $SpamaliasUsage['sa_count'];
-          if ($mailboxdata['percent_in_use'] >= 90) {
-            $mailboxdata['percent_class'] = "danger";
+          if ($mailboxdata['percent_in_use'] === '- ') {
+            $mailboxdata['percent_class'] = "info";
           }
           elseif ($mailboxdata['percent_in_use'] >= 75) {
             $mailboxdata['percent_class'] = "warning";
           }
+          elseif ($mailboxdata['percent_in_use'] >= 90) {
+            $mailboxdata['percent_class'] = "danger";
+          }
           else {
             $mailboxdata['percent_class'] = "success";
           }
diff --git a/data/web/js/site/mailbox.js b/data/web/js/site/mailbox.js
index f8aacac7..ba49892c 100644
--- a/data/web/js/site/mailbox.js
+++ b/data/web/js/site/mailbox.js
@@ -312,7 +312,8 @@ jQuery(function($){
         {"name":"domain","title":lang.domain,"breakpoints":"xs sm"},
         {"name":"quota","style":{"whiteSpace":"nowrap"},"title":lang.domain_quota,"formatter": function(value){
           res = value.split("/");
-          return humanFileSize(res[0]) + " / " + humanFileSize(res[1]);
+          var of_q = (res[1] == 0 ? "∞" : humanFileSize(res[1]));
+          return humanFileSize(res[0]) + " / " + of_q;
         },
         "sortValue": function(value){
           res = value.split("/");
diff --git a/data/web/modals/mailbox.php b/data/web/modals/mailbox.php
index 11abbc58..aeb88cca 100644
--- a/data/web/modals/mailbox.php
+++ b/data/web/modals/mailbox.php
@@ -43,8 +43,8 @@ if (!isset($_SESSION['mailcow_cc_role'])) {
               <br /><span id="quotaBadge" class="badge">max. - MiB</span>
             </label>
             <div class="col-sm-10">
-            <input type="text" class="form-control" name="quota" min="1" max="" id="addInputQuota" disabled value="<?=$lang['add']['select_domain'];?>" required>
-            <small class="help-block">min. 1</small>
+            <input type="text" class="form-control" name="quota" min="0" max="" id="addInputQuota" disabled value="<?=$lang['add']['select_domain'];?>" required>
+            <small class="help-block">0 = ∞</small>
             </div>
           </div>
           <div class="form-group">