diff --git a/list.c b/list.c
index 1f92ba1..6c2bf04 100644
--- a/list.c
+++ b/list.c
@@ -64,6 +64,11 @@ void list_reserve(List* self, size_t at_least) {
     self->cap = new_cap;
 }
 
+void list_set_len(List* self, size_t len) {
+    list_reserve(self, len);
+    self->len = len;
+}
+
 void* list_at_unchecked(List* self, size_t at) {
     union {
         uint8_t* as_byte;
diff --git a/list.h b/list.h
index 0d34494..91fecbd 100644
--- a/list.h
+++ b/list.h
@@ -17,6 +17,7 @@ extern List list_copy(const List* source);
 extern void list_empty(List* list);
 
 extern void list_reserve(List* self, size_t at_least);
+extern void list_set_len(List* self, size_t len);
 extern void* list_at(List* list, size_t at);
 extern void* list_at_unchecked(List* self, size_t at);