Every origami folder has met the same small frustration: a pattern that asks for the paper in thirds, and you are left eyeballing it, folding, unfolding, adjusting, until the panels are close but never quite even. The trick in this tutorial is the antidote. Four folds, no ruler, and the thirds land exactly right every time.

It works because of a neat piece of geometry hiding inside the square: fold once in half, swing one corner across, and the crossing point that appears marks your one-third line for you. Once you have done it a few times, this little move becomes one of those silent superpowers you reach for again and again — in boxes, in books, in any model with panels that need to line up.

Learn how to fold a square sheet of paper into thirds without a ruler. This is the simplest dividing method I have found so far: it takes only four steps and leaves just two creases on the paper. It only works with square paper, though.

Step 1

Make a crease by folding a square sheet of paper in half.

Step 2

Fold the bottom-left corner to meet the center point of the right edge.

Step 3

The spot where the left edge of the paper crosses the top edge is the division between 1/3 and 2/3. Mark this location with a pencil or by making a small pinch.

Step 4

Fold the 2/3-wide section in half to get a clean 1/3 + 1/3 + 1/3 division.