<?php
$data = array();  // assume this has stuff and has 12 elements

$itemsPerRow = 7;


$totalRows = ciel($data / $itemsPerRow); // ~1.714 -> 2

$currentRow = 1;

for($i = 0; $i < $totalRows; $i++) {


    if($i < count($data)) {
        $item = $data[$i];
        // print <td>$item</td>
    } else {
        // print <td></td>
    }

    if(($i % $itemsPerRow) == 0) {
        // print new table row
        $currentRow++;
    }
}