diff --git a/htdocs/fichinter/card.php b/htdocs/fichinter/card.php
index 8b4709d53d3..18f383d3ab3 100644
--- a/htdocs/fichinter/card.php
+++ b/htdocs/fichinter/card.php
@@ -1312,6 +1312,19 @@ if ($action == 'create') {
 		$formconfirm = $form->formconfirm($_SERVER["PHP_SELF"].'?id='.$object->id, $langs->trans('ToClone'), $langs->trans('ConfirmCloneIntervention', $object->ref), 'confirm_clone', $formquestion, 'yes', 1);
 	}
 
+	// Subtotal line form
+	if ($action == 'add_title_line') {
+		$langs->load('subtotals');
+		$type = 'title';
+		$depth_array = $object->getPossibleLevels($langs);
+		require dol_buildpath('/core/tpl/subtotal_create.tpl.php');
+	} elseif ($action == 'add_subtotal_line') {
+		$langs->load('subtotals');
+		$type = 'subtotal';
+		$titles = $object->getPossibleTitles();
+		require dol_buildpath('/core/tpl/subtotal_create.tpl.php');
+	}
+
 	if (!$formconfirm) {
 		$parameters = array('formConfirm' => $formconfirm, 'lineid' => $lineid);
 		$reshook = $hookmanager->executeHooks('formConfirm', $parameters, $object, $action); // Note that $action and $object may have been modified by hook
@@ -1766,6 +1779,29 @@ if ($action == 'create') {
 		$params = array();
 		if ($user->socid == 0) {
 			if ($action != 'editdescription' && ($action != 'presend')) {
+				// Subtotal
+				if ($object->status == Fichinter::STATUS_DRAFT && isModEnabled('subtotals') && getDolGlobalString('SUBTOTAL_TITLE_'.strtoupper($object->element))) {
+					$langs->load('subtotals');
+
+					$url_button = array();
+					$url_button[] = array(
+						'lang' => 'subtotals',
+						'enabled' => (isModEnabled('intervention') && $object->status == Fichinter::STATUS_DRAFT),
+						'perm' => (bool) $user->hasRight('intervention', 'creer'),
+						'label' => $langs->trans('AddTitleLine'),
+						'url' => '/fichinter/card.php?id='.$object->id.'&action=add_title_line&token='.newToken()
+					);
+
+					$url_button[] = array(
+						'lang' => 'subtotals',
+						'enabled' => (isModEnabled('intervention') && $object->status == Fichinter::STATUS_DRAFT),
+						'perm' => (bool) $user->hasRight('intervention', 'creer'),
+						'label' => $langs->trans('AddSubtotalLine'),
+						'url' => '/fichinter/card.php?id='.$object->id.'&action=add_subtotal_line&token='.newToken()
+					);
+					print dolGetButtonAction('', $langs->trans('Subtotal'), 'default', $url_button, '', true);
+				}
+
 				// Validate
 				if ($object->status == Fichinter::STATUS_DRAFT && (count($object->lines) > 0 || getDolGlobalString('FICHINTER_DISABLE_DETAILS') == '1')) {
 					if ((!getDolGlobalString('MAIN_USE_ADVANCED_PERMS') && $user->hasRight('ficheinter', 'creer')) || (getDolGlobalString('MAIN_USE_ADVANCED_PERMS') && $user->hasRight('ficheinter', 'ficheinter_advance', 'validate'))) {
diff --git a/htdocs/fichinter/class/fichinter.class.php b/htdocs/fichinter/class/fichinter.class.php
index 608ba13d61a..47b1d8a765e 100644
--- a/htdocs/fichinter/class/fichinter.class.php
+++ b/htdocs/fichinter/class/fichinter.class.php
@@ -4,7 +4,7 @@
  * Copyright (C) 2005-2012  Regis Houssin           <regis.houssin@inodbox.com>
  * Copyright (C) 2011-2020  Juanjo Menent           <jmenent@2byte.es>
  * Copyright (C) 2015       Marcos García           <marcosgdf@gmail.com>
- * Copyright (C) 2015-2020  Charlene Benke          <charlie@patas-monkey.com>
+ * Copyright (C) 2015-2025  Charlene Benke          <charlene@patas-monkey.com>
  * Copyright (C) 2018       Nicolas ZABOURI	        <info@inovea-conseil.com>
  * Copyright (C) 2018-2025  Frédéric France         <frederic.france@free.fr>
  * Copyright (C) 2023-2024  William Mead            <william.mead@manchenumerique.fr>
@@ -32,6 +32,8 @@
 require_once DOL_DOCUMENT_ROOT.'/core/class/commonobject.class.php';
 require_once DOL_DOCUMENT_ROOT.'/fichinter/class/fichinterligne.class.php';
 require_once DOL_DOCUMENT_ROOT.'/core/class/commonsignedobject.class.php';
+require_once DOL_DOCUMENT_ROOT.'/subtotals/class/commonsubtotal.class.php';
+
 
 /**
  *	Class to manage interventions
@@ -40,7 +42,7 @@ require_once DOL_DOCUMENT_ROOT.'/core/class/commonsignedobject.class.php';
  */
 class Fichinter extends CommonObject
 {
-	use CommonSignedObject;
+	use CommonSignedObject, CommonSubtotal;
 
 	/**
 	 * @var string		Prefix to check for any trigger code of any business class to prevent bad value for trigger code.