diff --git a/includes/model/User_model.php b/includes/model/User_model.php
index 18febf73..f22d0505 100644
--- a/includes/model/User_model.php
+++ b/includes/model/User_model.php
@@ -112,7 +112,7 @@ function User_validate_Nick($nick)
 {
     $nick = trim($nick);
 
-    if (strlen($nick) == 0 || strlen($nick) > 23) {
+    if (strlen($nick) == 0 || strlen($nick) > 24) {
         return new ValidationResult(false, $nick);
     }
     if (preg_match('/([^\p{L}\p{N}\-_. ]+)/ui', $nick)) {
diff --git a/includes/pages/admin_user.php b/includes/pages/admin_user.php
index 758ed8d9..e5ba9a2b 100644
--- a/includes/pages/admin_user.php
+++ b/includes/pages/admin_user.php
@@ -48,20 +48,20 @@ function admin_user()
         $html .= '<input type="hidden" name="Type" value="Normal">' . "\n";
         $html .= '<tr><td>' . "\n";
         $html .= '<table>' . "\n";
-        $html .= '  <tr><td>Nick</td><td>' . '<input size="40" name="eNick" value="' . $user_source->name . '" class="form-control"></td></tr>' . "\n";
+        $html .= '  <tr><td>Nick</td><td>' . '<input size="40" name="eNick" value="' . $user_source->name . '" class="form-control" maxlength="24"></td></tr>' . "\n";
         $html .= '  <tr><td>Last login</td><td><p class="help-block">'
             . ($user_source->last_login_at ? $user_source->last_login_at->format('Y-m-d H:i') : '-')
             . '</p></td></tr>' . "\n";
         if (config('enable_user_name')) {
-            $html .= '  <tr><td>Name</td><td>' . '<input size="40" name="eName" value="' . $user_source->personalData->last_name . '" class="form-control"></td></tr>' . "\n";
-            $html .= '  <tr><td>Vorname</td><td>' . '<input size="40" name="eVorname" value="' . $user_source->personalData->first_name . '" class="form-control"></td></tr>' . "\n";
+            $html .= '  <tr><td>Name</td><td>' . '<input size="40" name="eName" value="' . $user_source->personalData->last_name . '" class="form-control" maxlength="64"></td></tr>' . "\n";
+            $html .= '  <tr><td>Vorname</td><td>' . '<input size="40" name="eVorname" value="' . $user_source->personalData->first_name . '" class="form-control" maxlength="64"></td></tr>' . "\n";
         }
-        $html .= '  <tr><td>Handy</td><td>' . '<input type= "tel" size="40" name="eHandy" value="' . $user_source->contact->mobile . '" class="form-control"></td></tr>' . "\n";
+        $html .= '  <tr><td>Handy</td><td>' . '<input type= "tel" size="40" name="eHandy" value="' . $user_source->contact->mobile . '" class="form-control" maxlength="40"></td></tr>' . "\n";
         if (config('enable_dect')) {
-            $html .= '  <tr><td>DECT</td><td>' . '<input size="40" name="eDECT" value="' . $user_source->contact->dect . '" class="form-control"></td></tr>' . "\n";
+            $html .= '  <tr><td>DECT</td><td>' . '<input size="40" name="eDECT" value="' . $user_source->contact->dect . '" class="form-control" maxlength="40"></td></tr>' . "\n";
         }
         if ($user_source->settings->email_human) {
-            $html .= "  <tr><td>email</td><td>" . '<input type="email" size="40" name="eemail" value="' . $user_source->email . '" class="form-control"></td></tr>' . "\n";
+            $html .= "  <tr><td>email</td><td>" . '<input type="email" size="40" name="eemail" value="' . $user_source->email . '" class="form-control" maxlength="254"></td></tr>' . "\n";
         }
         $html .= '  <tr><td>Size</td><td>'
             . html_select_key(
diff --git a/includes/pages/guest_login.php b/includes/pages/guest_login.php
index f5c8e3a0..b4a8d0d4 100644
--- a/includes/pages/guest_login.php
+++ b/includes/pages/guest_login.php
@@ -78,7 +78,7 @@ function guest_register()
 
             if (!$nickValidation->isValid()) {
                 $valid = false;
-                $msg .= error(sprintf(__('Please enter a valid nick.') . ' ' . __('Use up to 23 letters, numbers, connecting punctuations or spaces for your nickname.'),
+                $msg .= error(sprintf(__('Please enter a valid nick.') . ' ' . __('Use up to 24 letters, numbers, connecting punctuations or spaces for your nickname.'),
                     $nick), true);
             }
             if (User::whereName($nick)->count() > 0) {
@@ -323,11 +323,11 @@ function guest_register()
                                 __('Nick') . ' ' . entry_required(),
                                 $nick,
                                 false,
-                                23,
+                                24,
                                 'nickname'
                             ),
                             form_info('',
-                                __('Use up to 23 letters, numbers, connecting punctuations or spaces for your nickname.'))
+                                __('Use up to 24 letters, numbers, connecting punctuations or spaces for your nickname.'))
                         ]),
                         div('col-sm-8', [
                             form_email(
@@ -335,7 +335,8 @@ function guest_register()
                                 __('E-Mail') . ' ' . entry_required(),
                                 $email,
                                 false,
-                                'email'
+                                'email',
+                                254
                             ),
                             form_checkbox(
                                 'email_shiftinfo',
@@ -395,18 +396,18 @@ function guest_register()
                             form_text('dect', __('DECT'), $dect, false, 40, 'tel-local')
                         ]) : '',
                         div($enable_dect ? 'col-sm-4' : 'col-sm-12', [
-                            form_text('mobile', __('Mobile'), $mobile, false, null, 'tel-national')
+                            form_text('mobile', __('Mobile'), $mobile, false, 40, 'tel-national')
                         ]),
                         $enable_pronoun ? div('col-sm-4', [
-                            form_text('pronoun', __('Pronoun'), $pronoun)
+                            form_text('pronoun', __('Pronoun'), $pronoun, false, 15)
                         ]) : '',
                     ]),
                     $enable_user_name ? div('row', [
                         div('col-sm-6', [
-                            form_text('prename', __('First name'), $preName, false, null, 'given-name')
+                            form_text('prename', __('First name'), $preName, false, 64, 'given-name')
                         ]),
                         div('col-sm-6', [
-                            form_text('lastname', __('Last name'), $lastName, false, null, 'family-name')
+                            form_text('lastname', __('Last name'), $lastName, false, 64, 'family-name')
                         ])
                     ]) : '',
                     form_info(entry_required() . ' = ' . __('Entry required!'))
diff --git a/includes/sys_form.php b/includes/sys_form.php
index ffc309cf..b4b7d3b1 100644
--- a/includes/sys_form.php
+++ b/includes/sys_form.php
@@ -276,17 +276,19 @@ function form_text_placeholder($name, $placeholder, $value, $disabled = false)
  * @param string      $value
  * @param bool        $disabled
  * @param string|null $autocomplete
+ * @param int|null    $maxlength
  *
  * @return string
  */
-function form_email($name, $label, $value, $disabled = false, $autocomplete = null)
+function form_email($name, $label, $value, $disabled = false, $autocomplete = null, $maxlength = null)
 {
     $disabled = $disabled ? ' disabled="disabled"' : '';
     $autocomplete = $autocomplete ? ' autocomplete="' . $autocomplete . '"' : '';
+    $maxlength = $maxlength ? ' maxlength=' . (int)$maxlength : '';
     return form_element(
         $label,
         '<input class="form-control" id="form_' . $name . '" type="email" name="' . $name . '" value="'
-        . htmlspecialchars($value) . '" ' . $disabled . $autocomplete . '/>',
+        . htmlspecialchars($value) . '" ' . $disabled . $autocomplete . $maxlength . '/>',
         'form_' . $name
     );
 }
diff --git a/includes/view/User_view.php b/includes/view/User_view.php
index bbd1adae..82aa8e0f 100644
--- a/includes/view/User_view.php
+++ b/includes/view/User_view.php
@@ -58,8 +58,12 @@ function User_settings_view(
                                 ? form_text('pronoun', __('Pronoun'), $personalData->pronoun, false, 15)
                                 . form_info('', __('Will be shown on your profile page and in angel lists.'))
                                 : '',
-                            $enable_user_name ? form_text('lastname', __('Last name'), $personalData->last_name) : '',
-                            $enable_user_name ? form_text('prename', __('First name'), $personalData->first_name) : '',
+                            $enable_user_name
+                                ? form_text('lastname', __('Last name'), $personalData->last_name, false, 64)
+                                : '',
+                            $enable_user_name
+                                ? form_text('prename', __('First name'), $personalData->first_name, false, 64)
+                                : '',
                             $enable_planned_arrival ? form_date(
                                 'planned_arrival_date',
                                 __('Planned date of arrival') . ' ' . entry_required(),
@@ -78,9 +82,9 @@ function User_settings_view(
                                 $buildup_start_date,
                                 $teardown_end_date
                             ) : '',
-                            $enable_dect ? form_text('dect', __('DECT'), $user_source->contact->dect) : '',
-                            form_text('mobile', __('Mobile'), $user_source->contact->mobile),
-                            form_text('mail', __('E-Mail') . ' ' . entry_required(), $user_source->email),
+                            $enable_dect ? form_text('dect', __('DECT'), $user_source->contact->dect, false, 40) : '',
+                            form_text('mobile', __('Mobile'), $user_source->contact->mobile, false, 40),
+                            form_text('mail', __('E-Mail') . ' ' . entry_required(), $user_source->email, false, 254),
                             form_checkbox(
                                 'email_shiftinfo',
                                 __(
diff --git a/resources/lang/de_DE/default.po b/resources/lang/de_DE/default.po
index ec3e3f66..d6dd2136 100644
--- a/resources/lang/de_DE/default.po
+++ b/resources/lang/de_DE/default.po
@@ -1547,10 +1547,10 @@ msgstr "Gib bitte einen erlaubten Nick an."
 #: includes/pages/guest_login.php:77 includes/pages/guest_login.php:277
 #: includes/view/User_view.php:42
 msgid ""
-"Use up to 23 letters, numbers, connecting punctuations or spaces for your "
+"Use up to 24 letters, numbers, connecting punctuations or spaces for your "
 "nickname."
 msgstr ""
-"Verwende bis zu 23 Buchstaben, Zahlen, verbindende Schriftzeichen (.-_) oder "
+"Verwende bis zu 24 Buchstaben, Zahlen, verbindende Schriftzeichen (.-_) oder "
 "Leerzeichen für deinen Nick."
 
 #: includes/pages/guest_login.php:82