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Pattern Scaling Calculator — Resize Pattern Pieces
Scale pattern pieces by percentage for enlarging or reducing designs.
On (default): everything scales together, like a photocopier. Off: keep the seam allowance at its original width and only scale the stitching lines.
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
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.
By default, yes — this calculator scales everything proportionally, just like a photocopier. Scale down 50% and a 1.5cm seam allowance becomes 0.75cm; scale up 200% and it becomes 3cm. If you would rather keep the seam allowance at its true width, switch off "Scale seam allowance with pattern" in Advanced Options. The designer method is to remove the seam allowance, scale the stitching line, then re-add the original allowance afterwards.
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.
Related Calculators
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Find the right pattern size from your body measurements.
Grading Calculator
Grade a pattern up or down between sizes with correct increments.
Length Adjustment Calculator
Lengthen or shorten pattern pieces at the correct adjustment lines.
Ease Calculator
Calculate wearing ease and design ease for comfortable garments.
Bust Adjustment Calculator
Calculate full bust or small bust adjustments for bodice patterns.
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Last updated: February 2026
All calculations are estimates. Always verify quantities before cutting or purchasing fabric.