How to Use a French Curve for Sewing

Updated March 23, 2017

The French curve, or designer’s curve, can be used to customise commercial garment patterns, which are based on standardised sizes intended to fit what’s considered to be average bodies. Standardised sizing won’t suit everyone, and that’s why knowing how to use a French curve comes in handy. This drafting tool can be used to easily customise commercial patterns, allowing sewers to adjust them to fit curvaceous figures or lower a neckline.

Accommodate a shapely figure by creating a curve where needed, even if the original pattern line is straight. Accomplish this by adding your measurements to the corresponding portion of the pattern you want to change and using the curved side of a French curve to join the points you drew.

Customise a skirt or trousers pattern. You can create a skirt or trousers pattern that seamlessly fits your hips, by moving a French curve along the side seams until the curves closely correspond to your body measurements from your waist to your hips. Draw the new curves. This waist-to-hip pattern alteration method also can be used for dresses and long jackets.

Adjust a pattern for high hips by positioning a French curve so that its straight end is pointed toward the hemline to achieve the appropriate curve to fit your measurements. Change a high hip curve to a straight hip curve by positioning the French curve in the opposite direction.

Redraw a dart to match your bust line without causing the sides of the pattern to become lopsided. To keep the sides even after realigning the dart, use the edge of a French curve that matches your pattern line to create a new cutting line for your pattern piece.

Create a lower neckline on a pattern by first deciding how deep you want the new neckline to be. Denote that measurement on the pattern, and then line up your French curve with that mark so that it crosses the pattern’s cutting line for the corresponding shoulder, which shouldn’t be changed. Redraw the neckline by following the new line created by this placement.


Use a French curve that has a numbered edge to simplify keeping track of how much of the curve is used for pattern adjustments.

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About the Author

Frances Burks has more than 15 years experience in writing positions, including work as a news analyst for executive briefings and as an Associated Press journalist. Burks has banking and business development experience, and she has written numerous articles on consumer issues and home improvement. Burks holds a bachelor's degree in political science from the University of Michigan.