When would I scale a pattern?

Scaling is used when resizing craft patterns (toys, bags, home decor), miniature samples, or when a pattern needs uniform enlarging/reducing. It is different from garment grading, which changes specific body measurement areas.

Does scaling change seam allowances?

Yes, scaling changes everything proportionally, including seam allowances. If you scale down 50%, a 1.5cm seam allowance becomes 0.75cm. You may want to re-mark seam allowances at the original width after scaling.

How do I physically scale a pattern?

Use a photocopier or printer with a percentage setting. For hand scaling, multiply every measurement by the scale factor (e.g., 75% = multiply by 0.75). Mark key points, then connect with smooth curves.

SewCalcs

Pattern Scaling Calculator — Resize Pattern Pieces

Scale pattern pieces by percentage for enlarging or reducing designs.

Original Width

Original Height

Scale Percentage

100% = same size, 200% = double

How We Calculate This

Scaling multiplies all dimensions by the scale factor. At 200%, every measurement doubles. At 50%, every measurement halves.

The formula

New dimension = Original dimension × (Scale% ÷ 100)

New area = Original area × (Scale% ÷ 100)²

Frequently Asked Questions

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Last updated: February 2026

All calculations are estimates. Always verify quantities before cutting or purchasing fabric.