diff --git a/common.php b/common.php
index 7fc7f95f..14d4a5db 100644
--- a/common.php
+++ b/common.php
@@ -122,38 +122,31 @@ if (!IS_CLI) {
 	session_start();
 }
 
-// basedir
-$basedir = '';
-$tmp = explode('/', $_SERVER['SCRIPT_NAME']);
-$size = count($tmp) - 1;
-for($i = 1; $i < $size; $i++)
-	$basedir .= '/' . $tmp[$i];
-
-$basedir = str_replace(['/' . ADMIN_PANEL_FOLDER, '/install', '/tools'], '', $basedir);
-define('BASE_DIR', $basedir);
-
-if(!IS_CLI) {
-	if (isset($_SERVER['HTTP_HOST'][0])) {
-		$baseHost = $_SERVER['HTTP_HOST'];
-	} else {
-		if (isset($_SERVER['SERVER_NAME'][0])) {
-			$baseHost = $_SERVER['SERVER_NAME'];
-		} else {
-			$baseHost = $_SERVER['SERVER_ADDR'];
-		}
-	}
-
-	define('SERVER_URL', 'http' . (isHttps() ? 's' : '') . '://' . $baseHost);
-	define('BASE_URL', SERVER_URL . BASE_DIR . '/');
-	define('ADMIN_URL', SERVER_URL . BASE_DIR . '/' . ADMIN_PANEL_FOLDER . '/');
-
-	//define('CURRENT_URL', BASE_URL . $_SERVER['REQUEST_URI']);
-}
-
 if (file_exists(BASE . 'config.local.php')) {
 	require BASE . 'config.local.php';
 }
 
+if(!IS_CLI) {
+	require SYSTEM . 'base.php';
+	define('BASE_DIR', $baseDir);
+
+	if (isset($config['site_url'])) {
+		$hasSlashAtEnd = ($config['site_url'][strlen($config['site_url']) - 1] == '/');
+
+		define('SERVER_URL', $config['site_url']);
+		define('BASE_URL', SERVER_URL . ($hasSlashAtEnd ? '' : '/'));
+		define('ADMIN_URL', SERVER_URL . ($hasSlashAtEnd ? '' : '/') . ADMIN_PANEL_FOLDER . '/');
+	}
+	else {
+		define('SERVER_URL', 'http' . (isHttps() ? 's' : '') . '://' . $baseHost);
+		define('BASE_URL', SERVER_URL . BASE_DIR . '/');
+		define('ADMIN_URL', SERVER_URL . BASE_DIR . '/' . ADMIN_PANEL_FOLDER . '/');
+
+		//define('CURRENT_URL', BASE_URL . $_SERVER['REQUEST_URI']);
+	}
+
+}
+
 /** @var array $config */
 ini_set('log_errors', 1);
 if(@$config['env'] === 'dev' || defined('MYAAC_INSTALL')) {
diff --git a/install/steps/4-config.php b/install/steps/4-config.php
index 325b97f1..342edd06 100644
--- a/install/steps/4-config.php
+++ b/install/steps/4-config.php
@@ -10,6 +10,14 @@ foreach($config['clients'] as $client) {
 	$clients[$client] = $client_version;
 }
 
+if (empty($_SESSION['var_site_url'])) {
+	//require SYSTEM . 'base.php';
+	$serverUrl = 'http' . (isHttps() ? 's' : '') . '://' . $baseHost;
+	$siteURL = $serverUrl . $baseDir;
+
+	$_SESSION['var_site_url'] = $siteURL;
+}
+
 $twig->display('install.config.html.twig', array(
 	'clients' => $clients,
 	'timezones' => DateTimeZone::listIdentifiers(),
diff --git a/system/base.php b/system/base.php
new file mode 100644
index 00000000..a0ba4e6b
--- /dev/null
+++ b/system/base.php
@@ -0,0 +1,19 @@
+<?php
+
+$baseDir = '';
+$tmp = explode('/', $_SERVER['SCRIPT_NAME']);
+$size = count($tmp) - 1;
+for($i = 1; $i < $size; $i++)
+	$baseDir .= '/' . $tmp[$i];
+
+$baseDir = str_replace(['/' . ADMIN_PANEL_FOLDER, '/install', '/tools'], '', $baseDir);
+
+if (isset($_SERVER['HTTP_HOST'][0])) {
+	$baseHost = $_SERVER['HTTP_HOST'];
+} else {
+	if (isset($_SERVER['SERVER_NAME'][0])) {
+		$baseHost = $_SERVER['SERVER_NAME'];
+	} else {
+		$baseHost = $_SERVER['SERVER_ADDR'];
+	}
+}
diff --git a/system/locale/de/install.php b/system/locale/de/install.php
index ad354609..927da34b 100644
--- a/system/locale/de/install.php
+++ b/system/locale/de/install.php
@@ -48,6 +48,8 @@ $locale['step_config'] = 'Konfiguration';
 $locale['step_config_title'] = 'Grundkonfiguration';
 $locale['step_config_server_path'] = 'Serverpfad';
 $locale['step_config_server_path_desc'] = 'Pfad zu Ihrem TFS-Hauptverzeichnis, in dem sich die config.lua befinden.';
+$locale['step_config_site_url'] = 'Website URL';
+$locale['step_config_site_url_desc'] = 'Ihre Website-Adresse.';
 $locale['step_config_mail_admin'] = 'Admin E-Mail';
 $locale['step_config_mail_admin_desc'] = 'Adresse, an die E-Mails aus dem Kontaktformular gesendet werden, z. B. admin@gmail.com';
 $locale['step_config_mail_admin_error'] = 'Admin E-Mail ist nicht korrekt.';
diff --git a/system/locale/en/install.php b/system/locale/en/install.php
index 0cbd29ad..376e82c3 100644
--- a/system/locale/en/install.php
+++ b/system/locale/en/install.php
@@ -52,6 +52,8 @@ $locale['step_config'] = 'Configuration';
 $locale['step_config_title'] = 'Basic configuration';
 $locale['step_config_server_path'] = 'Server path';
 $locale['step_config_server_path_desc'] = 'Path to your TFS main directory, where you have config.lua located.';
+$locale['step_config_site_url'] = 'Website URL';
+$locale['step_config_site_url_desc'] = 'Your website address.';
 $locale['step_config_mail_admin'] = 'Admin Email';
 $locale['step_config_mail_admin_desc'] = 'Address where emails from contact form will be delivered, for example admin@gmail.com';
 $locale['step_config_mail_admin_error'] = 'Admin Email is not correct.';
diff --git a/system/locale/pl/install.php b/system/locale/pl/install.php
index 5b6725cf..159a7d8f 100644
--- a/system/locale/pl/install.php
+++ b/system/locale/pl/install.php
@@ -52,6 +52,8 @@ $locale['step_config'] = 'Konfiguracja';
 $locale['step_config_title'] = 'Podstawowa konfiguracja';
 $locale['step_config_server_path'] = 'Ścieżka do serwera';
 $locale['step_config_server_path_desc'] = 'Ścieżka do Twojego folderu z TFS, gdzie znajduje się plik config.lua.';
+$locale['step_config_server_url'] = 'Adres strony';
+$locale['step_config_server_url_desc'] = 'Adres tej strony www.';
 $locale['step_config_mail_admin'] = 'E-Mail admina';
 $locale['step_config_mail_admin_desc'] = 'Na ten adres będą dostarczane E-Maile z formularza kontaktowego, przykładowo admin@gmail.com';
 $locale['step_config_mail_admin_error'] = 'E-Mail admina jest niepoprawny.';
diff --git a/system/settings.php b/system/settings.php
index a7a5ee0a..7a7a48a6 100644
--- a/system/settings.php
+++ b/system/settings.php
@@ -21,6 +21,11 @@ $defaultTemplate = in_array('kathrine', $templates) ? 'kathrine' : $templates[0]
 
 global $db;
 
+require SYSTEM . 'base.php';
+
+$serverUrl = 'http' . (isHttps() ? 's' : '') . '://' . $baseHost;
+$siteURL = $serverUrl . $baseDir;
+
 return [
 	'name' => 'MyAAC',
 	'settings' => [
@@ -32,6 +37,13 @@ return [
 			'type' => 'section',
 			'title' => 'General'
 		],
+		'site_url' => [
+			'name' => 'Website URL',
+			'type' => 'text',
+			'desc' => 'Website address of this MyAAC instance',
+			'default' => $siteURL,
+			'is_config' => true,
+		],
 		'env' => [
 			'name' => 'App Environment',
 			'type' => 'options',
diff --git a/system/templates/install.config.html.twig b/system/templates/install.config.html.twig
index ab4fc361..8c0aa50a 100644
--- a/system/templates/install.config.html.twig
+++ b/system/templates/install.config.html.twig
@@ -9,7 +9,7 @@
 <form action="{{ constant('BASE_URL') }}install/" method="post" autocomplete="off">
 	<input type="hidden" name="step" id="step" value="database" />
 
-	{% for value in ['server_path'] %}
+	{% for value in ['site_url', 'server_path'] %}
 	<div class="form-group mb-2">
 		<label for="vars_{{ value }}">{{ locale['step_config_' ~ value]  }}</label>
 		<input class="form-control" type="{% if value == 'mail_admin' %}email{% else %}text{% endif %}" name="vars[{{ value }}]" id="vars_{{ value }}"{% if session['var_' ~ value] is not null %} value="{{ session['var_' ~ value] }}"{% endif %}/>