How to Make a Sturdy Cardboard Storage Box With Handles

A shipping box already has four walls, a base and square corners. What it lacks is stiffness at the rim, somewhere to grip it and a surface you would want to look at on a shelf.

This project turns one clean shipping box into a cardboard storage box with doubled walls, a second base layer, reinforced oval handles and a paper or fabric cover. The worked example starts from a box 12 in (30.5 cm) long, 9 in (23 cm) wide and 10 in (25.5 cm) tall and finishes 7 in (18 cm) high.

Choose the box and the finished height

Pick a clean, dry single-wall corrugated box with uncrushed corners. Peel off plastic tape and labels, glue the bottom flaps shut with white (PVA) glue and cover the outside seam with paper tape.

Decide the finished height from your shelf space. Then stand the top flaps straight up and measure the full wall from the base to the flap tips: 10 in of wall plus 4 1/2 in (11.5 cm) of flap, or 14 1/2 in (37 cm), in the example. Everything above the finished height will fold down inside to line the walls.

Mark the fold and the cut

You need three lines around the outside of the box, all measured up from the base. For a finished height of 7 in:

1. First score line at the finished height: 7 in.
2. Second score line one board thickness higher: 7 1/8 in (18.3 cm). The two scores let the board wrap over its own thickness instead of cracking.
3. Cut line at twice the finished height less 1/4 in (6 mm): 14 in less 1/4 in is 13 3/4 in (35 cm).

In the example, the cut line is 3/4 in (2 cm) below the flap tips, so that much is trimmed off each flap. The lining will then be 6 5/8 in (16.8 cm) long, which stops 3/8 in (1 cm) above the floor and leaves room for the second base layer.

If your box is too short to reach the cut line, skip the trimming. The lining will still double the rim and the handle area.

Cut down and fold the lining

1. Trim the flaps at the cut line.
2. Slit each of the four corners from the top down to the first score line, and no further.
3. Score both lines on every wall and fold each flap inward and down.
4. Trim about 1/8 in (3 mm) from both side edges of the two long flaps, and about 1/4 in from both side edges of the two short flaps, so they sit side by side inside the corners.
5. Dry fit all four, then glue the long flaps down first and the short flaps second. Hold the rim with binder clips or clothespins for roughly 20 to 30 minutes.

Doubling walls is one of several methods in the guide to making cardboard stiffer.

Add a second base layer

Measure the floor between the linings and cut a panel to fit, close to 11 3/4 x 8 3/4 in (30 x 22 cm) in the example. Test it dry, then turn it so its flutes cross those of the box floor, glue it in with a thin, even coat and weigh it down with books while it sets.

Cut and reinforce the handles

The handles go in the two short walls, cut through both layers once the lining glue has dried for several hours. Each opening is an oval slot 4 in (10 cm) wide and 1 1/4 in (3.2 cm) tall.

1. Find the center of the short wall: 4 1/2 in from either corner on a 9 in wall.
2. Draw a horizontal line 2 1/8 in (5.4 cm) below the rim. This is the middle of the slot.
3. On that line, mark two points 1 3/8 in (3.5 cm) either side of center. With a compass, draw a circle of 5/8 in (1.6 cm) radius around each point.
4. Join the tops and the bottoms of the two circles with straight lines. The slot spans 2 3/4 in between centers plus 5/8 in at each end, which is 4 in.
5. Cut out the slot.

For each handle, cut a patch 6 x 3 1/4 in (15 x 8.3 cm) with its flutes running the long way. Cut the same slot in its center, which leaves a 1 in (2.5 cm) border all around. Glue the patch inside the box with the slots lined up and clip it until the glue grabs.

Wrap short strips of paper tape through each slot to round over the cut edge.

Cover the outside

Paper or cotton fabric both work. Cut one strip long enough to wrap all four walls with a 1/2 in (12 mm) overlap, which is 42 1/2 in (108 cm) for the example, or join two shorter pieces at a corner. Make it 9 in tall: 7 in of wall, 1 in to turn under the base and 1 in to fold over the rim.

Use a thin coat of white glue and smooth from the center of each wall toward the corners. Slit the cover in an X across each handle and fold the points inside. The guide to painting and covering cardboard without warping explains how to keep panels flat.

Add a label holder

Cut a frame 3 1/2 x 2 in (9 x 5 cm) from thin paperboard and cut a window 2 1/2 x 1 in (6.4 x 2.5 cm) in its center. Glue it to one short wall along the two sides and the bottom only, with a glue line about 1/4 in wide. The open top forms a pocket for a slip of card just under 3 in wide.

Resizing and sensible use

The method scales to any box: score at the finished height and one thickness above it, and cut at twice the height less 1/4 in. On narrow walls, shorten the handle slot by moving the circle centers closer together.

If you have no suitable box, or want a small lidded one, you can build a box from a flat net instead. Either way, use the finished box for light, dry household items such as linens, yarn or craft supplies, and lift a full box from underneath.