What size paper box fits on one page?
A box unfolds into its floor, walls and flaps, so the sheet limits how big a one-page box can be. On 65 lb card stock, the largest square boxes on one Letter page are, inside, 2.44 × 2.44 × 1.52 in for a box with lid shaped like the mini gift box, with its 0.625 in lid, 2.12 in on each side for a tuck box and 2.41 × 2.41 × 0.96 in for a drawer box.
A4 is narrower than Letter (210 vs 215.9 mm) but taller (297 vs 279.4 mm), so on A4 the tuck and drawer boxes come out a little smaller and the box with lid a little bigger. A two-piece paper box template a little bigger than that still needs no tape: the small gift box and the square drawer box print each piece whole on its own page. Past about 3 in square, depending on the depth, the pieces are split over pages you tape together; the page count next to the size tells you which.
Small gift box3 × 3 × 2 in
Mini gift box with lid2 × 2 × 1.25 in
Square tuck box2 × 2 × 2 in
Square drawer box2.5 × 2.5 × 1 in
Drawn to the same scale