Origami Paper Size Calculator
Calculate the ideal paper size for any origami model based on desired finished size.
Covers square, rectangle, and A-series paper.
How origami paper size relates to finished model size
In origami, the finished model is always smaller than the starting sheet. The ratio between paper size and model size depends on the complexity of the design. Simple models use more of the paper’s area, while complex models with many layers fold the paper down to a smaller fraction of its original size.
The paper-to-model ratio formula:
Required paper size = Desired model size × Folding ratio
The folding ratio depends on model complexity:
| Complexity | Folding Ratio | Examples |
|---|---|---|
| Simple (few folds) | 2.5 - 3× | Boat, cup, hat |
| Moderate (20-30 folds) | 3 - 4× | Crane, frog, lily |
| Complex (40-60 folds) | 4 - 6× | Dragon, unicorn, modular units |
| Super complex (60+ folds) | 6 - 10× | Insects, detailed animals |
Standard origami paper (kami) sizes:
| Size | Dimensions | Best For |
|---|---|---|
| 7.5 cm | 7.5 × 7.5 cm (3") | Tiny models, earrings, decorations |
| 15 cm | 15 × 15 cm (6") | Most standard models, the most common size |
| 20 cm | 20 × 20 cm (8") | Moderately complex models |
| 24 cm | 24 × 24 cm (9.5") | Complex models |
| 35 cm | 35 × 35 cm (14") | Super complex, display pieces |
Worked example — folding a crane:
You want a finished crane about 8 cm tall. Cranes are moderate complexity with a folding ratio of about 3.5×.
Paper needed = 8 cm × 3.5 = 28 cm
The nearest standard size above 28 cm is 35 cm. So use a 35 cm sheet, or cut a custom 28 cm square from larger paper.
Paper weight matters too. Standard kami is 60-70 gsm. For complex models with many layers, thinner paper (40-50 gsm, such as tissue foil) folds more crisply. For simple models, thicker paper (80-100 gsm) holds shape better.
Rectangle paper: Some traditional models (like the masu box) use rectangular paper. A4 paper (210 × 297 mm) has a 1:√2 ratio and works for many rectangle-based designs. US Letter (216 × 279 mm) is close to 1:1.29.