What scale ratio should I use to enlarge a pattern by 20%?

Enter 1.2 as the ratio. Multiplying by 1.2 increases every measurement by 20%. To reduce by 20%, use 0.8.

Can I scale measurements in different units?

Yes. The calculator works with any unit — inches, centimeters, millimeters, or stitch counts. Just keep all values in the same unit before scaling.

How do I calculate the ratio between two sizes?

Divide the target measurement by the original measurement. For example, if your original chest is 36 inches and the target is 40 inches, the ratio is 40 ÷ 36 ≈ 1.111.

Does scaling affect ease allowances?

Yes — scaling multiplies every number including ease. If you only want to change the body measurements and keep ease the same, subtract ease before scaling and add it back afterward.

How many measurements can I scale at once?

There is no hard limit. Enter as many lines as you need; the table will scroll to show all results.

Pattern Scaling Calculator

Enter your original measurements and a scale ratio to instantly resize any sewing or knitting pattern.

Original Measurements

One measurement per line (numbers only)

Scale Ratio

Decimal Places

Quick ratios:

Scaled Results

Enter measurements and a ratio,
then click Scale Pattern.

#	Original	Scaled	Difference

Summary

The Pattern Scaling Calculator lets crafters resize sewing or knitting patterns by entering original measurements and a custom scale ratio. It handles multiple measurements at once and instantly outputs scaled values with full precision. Whether you are grading up a dress pattern or adjusting a knitting gauge, this tool eliminates manual arithmetic and avoids costly mistakes.

How it works

Enter each original measurement on its own row (one number per line).
Type your desired scale ratio — for example, 1.25 to enlarge by 25% or 0.8 to reduce by 20%.
Click "Scale Pattern" and all measurements are multiplied by the ratio instantly.
Review the side-by-side table showing original vs. scaled values.
Copy the results or clear the inputs to start a new calculation.

Use cases

Grade a commercial sewing pattern up or down by a percentage.
Convert knitting stitch and row counts when switching yarn gauges.
Resize a quilt block pattern to a different finished size.
Scale embroidery transfer dimensions to fit a new hoop size.
Adjust a children's pattern to fit a specific child's measurements.
Proportionally enlarge or shrink any set of measurements for craft projects.

Frequently Asked Questions

Last updated: 2026-05-29 · Reviewed by Nham Vu