To reverse an array_chunk, use array_merge, passing the chunks as a variadic: <?php $array = [1, 2, 3, 4, 5, 6, 7, 8, 9]; $chunks = array_chunk($array, 3); // $chunks = [[1, 2, 3], [4, 5, 6], [7, 8, 9]] $de_chunked = array_merge(…$chunks); // $de_chunked = [1, 2, 3, 4, 5, 6, 7, 8, 9] ?>