How to Make a Cardboard Chair. You can create an environmentally friendly chair out of a large cardboard box in just a few minutes. This pattern makes a simple side chair with a straight back, which is sturdy enough to support an average adult.
Open the cardboard box so it lays flat, then measure it. You want the box to be at least 45 inches wide and 60 inches high.
Place the cardboard in front of you in a vertical layout. Use the bottom edge of the flattened box as the bottom side of a rectangle that is 45 inches long and 15 inches high. Draw the rectangle, then draw dividing lines inside it at 15-inch intervals to make three 15-inch squares.
Extend the lines up from the middle square in Step 2 an additional 45 inches. Divide it into three 15-inch squares. Finish by drawing a horizontal line at the top of the third square. You should have a T-shaped drawing, made of a total of six 15-inch squares.
Cut out the T-shape and turn it so it looks like an upside down T. Fold back the two squares that "cross" the T until they touch each other behind, forming a triangle. Rotate the cardboard so the triangle sits on the ground. This is the base of your chair.
Fold down the cardboard that now sticks straight up, so it sits on the triangle and is parallel with the ground. The square sitting on top of the triangle is the seat. Fold the last two squares at a 90-degree angle, so they stick straight up.
Press the top square down so that it forms a double-thick chair back. Use whatever means you like to secure the fold. What was once a cardboard box is now a chair. Have a seat.