Which moving boxes are strongest?

Look for the box maker's certificate printed on the bottom flap. ECT 32 is a normal moving box; ECT 44 or a "heavy duty" or double-wall box is for books, tools and kitchen goods.

Store-brand moving boxes from the big home and truck-rental stores are generally fine at ECT 32; pay for heavy duty only where the weight is.

Reused grocery and liquor boxes are free and good for small heavy things, but skip any that are soft, damp or have held food — they crush and can bring pests.

Source: Corrugated box standards (Edge Crush Test) · Checked October 2026