Origami Paper Size Calculator (Model Size, Squares from A4, Modular Units)

How it works

finished size = paper size × model ratio (crane wingspan 0.85, masu box side 1 ÷ 2√2 = 0.354, sonobe cube edge ≈ 0.35 …) · squares per sheet = ⌊W ÷ s⌋ × ⌊H ÷ s⌋ · largest square from a sheet = its short side

Origami scales perfectly: a model folded from a square twice the size is exactly twice as large in every dimension, so each design has a fixed ratio between paper edge and finished size that can be measured once and reused — the masu box's side is the square's edge divided by two root two, a crane's wingspan roughly 85% of the paper. Knowing the ratio turns "I want a 12 cm crane" into a paper size, and the rest is arithmetic on cutting squares from the rectangular sheets that printers use, where the offcut strip from squaring an A4 sheet is itself useful. Modular designs multiply the paper need by their unit count, and paper weight matters more than size once many layers stack up.

Worked example

For 12 cm-wingspan cranes, cut 12 ÷ 0.85 ≈ 14.1 cm squares — the standard 15 cm kami gives a 12.8 cm crane. Twelve cranes need twelve squares; from A4 you get two 14.1 cm squares per sheet (33% offcut), so six sheets. A 60-unit kusudama from 7.5 cm squares takes ten A4 sheets (6 per sheet) and makes a ball about 9 cm across.

Frequently asked questions