Sewing Techniques: Lengthen or Shorten a swimsuit pattern

Swimwear especially one pieces really don’t give you much room to finalise the length once you are finished like you would for a dress or a skirt. So here are some tips and tricks to make getting it right for you.

Choosing your size

Swimwear needs to use the negative ease of the pattern/fabric combination in order to fit correctly. 

Measure yourself. Bust, waist and hip. If the style has a lower back then also measure your bust from side seam to side seam over the breasts.

Measure your flat pattern pieces and subtract the seam allowance. Seam Allowance is 1cm (if you are not using a Measure Twice Cut Once pattern be sure to check the individual brands instructions for seam allowances). Add front and back measurements together to get the circumference. Check your stretch % and use that to calculate your size. If you aren’t confident doing that, then subtract 5cm from the total circumference and start with that size.

Lengthening or Shortening

Measure from your crotch to the neckline position of your chosen style. Stand straight, do not lean forward. Look in a full lenth mirror if it helps you see the correct positioning.

On the pattern piece front measure from crotch to neckline and subtract the seam allowances. 

Compare the 2 measurements and determine if you want to lengthen or shorten? You want a small amount of negative ease in this case but no more than 3cm unless your fabric has a very high stretch %.

Use the lengthen/shorten lines indicated on the pattern. Spread the amount you need to lengthen or shorten throughout the pattern in order to preserve proportions.

**Proportions are highly relevant in all pattern making but seeing as how swim is the smallest amount of fabric covering the most curved parts of your body it counts more than ever. Always spread or reduce evenly throughout the pattern taking into account your own body shape. If your bust needs significantly more length than your belly/bottom then add more there. The key is to maintain the desired look of the design while also taking into account your own body shaping.

Once the required amount is added or subtracted, re draw the side seams. Maintain a smooth and even seam line to ensure it fits the contours of your body.

Check other areas before proceeding

Measure side seams to ensure they still match as in front and back are same lengths or back meets to the correct point on the front in the case of swimwear with low backs.

Check that the new body length has not affected other areas of the swimsuit in terms of coverage. Key areas to check are centre front necklines, underarms and bottom coverage. Again measure your body and measure your pattern pieces to determine if any changes need to be made.

I hope this helps you determine your correct length for swimwear, if you have any questions drop them in the comments and I’ll answer them in case anyone else has the same query.