$shipping = number_format($totalCost, 2, ".", ","); if($shipping < 100.00){ //if great then 100 add the following $shipping = $shipping + 5.95; }elseif ($shipping > 100 && $shipping < 200){ //if between 100 - 200 add the following value $shipping = $shipping + 10.00; }elseif ($shipping > 300.00){ //right here is where I'm stuck, I want to add 1 dollar to every additional 100 after 200, so 300 would be 11.00, then 400 would be 12.00, and so on foreach () $shipping = $shipping + 11.00; }