diff --git a/src/api/controller/accounts.py b/src/api/controller/accounts.py
index 8ef7102..7d69229 100644
--- a/src/api/controller/accounts.py
+++ b/src/api/controller/accounts.py
@@ -54,8 +54,8 @@ def get_months(account_id):
     session = db.session
 
     query = session.query(
-      distinct(cast(extract("year", Entry.operation_date), db.String)).label("year"),
-      cast(extract("month", Entry.operation_date), db.String).label("month")
+      distinct(func.lpad(cast(extract("year", Entry.operation_date), db.String), 4, '0')).label("year"),
+      func.lpad(cast(extract("month", Entry.operation_date), db.String), 2, '0').label("month")
     ).filter(Entry.account_id == account_id).order_by("year", "month")
 
     return json.dumps([{