diff --git a/libraries/libft/build/libft.mk b/libraries/libft/build/libft.mk
index 1a554cc2..654e7673 100644
--- a/libraries/libft/build/libft.mk
+++ b/libraries/libft/build/libft.mk
@@ -78,6 +78,7 @@ SRC		+=	$(addprefix $(DIR), \
 			ft_lstlast_d.c \
 			ft_lstnew_back_d.c \
 			ft_lstnew_d.c \
+			ft_lstsize_d.c \
 )
 
 #  Singly-linked:
diff --git a/libraries/libft/inc/libft.h b/libraries/libft/inc/libft.h
index 1bf17c37..985d0407 100644
--- a/libraries/libft/inc/libft.h
+++ b/libraries/libft/inc/libft.h
@@ -6,7 +6,7 @@
 /*   By: ldulling <ldulling@student.42.fr>          +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2023/09/24 16:17:46 by ldulling          #+#    #+#             */
-/*   Updated: 2024/06/07 18:59:14 by ldulling         ###   ########.fr       */
+/*   Updated: 2024/06/28 19:31:02 by ldulling         ###   ########.fr       */
 /*                                                                            */
 /* ************************************************************************** */
 
@@ -60,6 +60,7 @@ void		ft_lstiter_d(t_list_d *lst, void (*f)(void *));
 t_list_d	*ft_lstlast_d(t_list_d *lst);
 bool		ft_lstnew_back_d(t_list_d **lst, void *content);
 t_list_d	*ft_lstnew_d(void *content);
+int			ft_lstsize_d(t_list_d *lst);
 
 \
 /* Lists singly-linked */
diff --git a/libraries/libft/src/lists/doubly_linked/ft_lstsize_d.c b/libraries/libft/src/lists/doubly_linked/ft_lstsize_d.c
new file mode 100644
index 00000000..0f1b81a4
--- /dev/null
+++ b/libraries/libft/src/lists/doubly_linked/ft_lstsize_d.c
@@ -0,0 +1,28 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_lstsize_d.c                                     :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: ldulling <ldulling@student.42.fr>          +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2023/09/24 16:08:06 by ldulling          #+#    #+#             */
+/*   Updated: 2024/06/28 19:30:32 by ldulling         ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "libft.h"
+
+int	ft_lstsize_d(t_list_d *lst)
+{
+	int			n;
+	t_list_d	*cur;
+
+	n = 0;
+	cur = lst;
+	while (cur != NULL)
+	{
+		n++;
+		cur = cur->next;
+	}
+	return (n);
+}