Swimsuits Part 2: a pattern for bikini bottoms

These are the pieces of my pattern for high waisted bikini bottoms:

The pattern comes in two sizes: “small” (24-30″ waist, 33-38″ bottom) and “large” (28-36″ waist, 36-46″ bottom). I don’t think these sizes correspond very well to standard sizes, they’re just the two sizes I have my pattern in. Use the measurements above, or the more detailed measurements bellow to figure out which size is better for you. To use the pattern just click on each of these pictures and keep clicking until you get the full size image. Print it out, check that the 1″ mark really is 1″, tape the pieces together at the stars and dots, and cut out your swimsuit.

Swimsuits are stretchy, and these two standard sizes will fit a range of people pretty well, but I always adjust them to more closely fit the person they’re for. To do this you will need these measurements.

1. Waist. Measure where you want the top of the swimsuit to be. For this high waisted style that will be your natural waist, somewhere near your belly button.
2. Bottom. Measure around the largest part of your lower body.
3. Thigh. Measure around the top of your thigh.
4. Side height. The length you want the side to be, from the edge of the leg opening to the waist.
5. Front length. From the waist in front to crotch center.
6. Back length. From the waist in back to crotch center.

Next, scale those numbers for swimsuit fabric. Swimsuit fabric is stretchy, and you want the swimsuit to stretch a bit when you wear it. This will help it stay on and keep it from sagging in an unflattering way. Your swimsuit should be at 10% – 30% smaller than you. All of the swimsuits shown here are on the 10% end, because we’re not fans of the skin-tight slightly squished look a smaller swimsuit gives, but we’re also not serious swimmers. A tighter swimsuit is more secure. For a splashing around in the ocean swimsuit, multiply all your measurements by 0.9; for a looking-cute-while-swimming suit, multiply by 0.8; for a bikini you can dive in, multiply by 0.7 and take the elastic option whenever there’s a choice of how to finish an edge.

Using your adjusted measurements, make sure that the pattern measurements match your measurements. Modify the pattern as needed, keeping in mind that it will stretch more over your bottom, while the elastic or waist band can bring it in slightly at the waist (my measurements are waist 25″, bottom 38″ and the size small fits me perfectly).

The pattern measurements for the size small are approximately:

1. 27″
2. 33″
3. 16″
4. 8″
5. 10″
6. 11″

For the large:

1. 29″
2. 36″
3. 17″
4. 9″
5. 10″
6. 12″

Next: sewing together your bikini bottoms.

This entry was posted in Sewing, Swimsuits, Tutorials. Bookmark the permalink.

17 Responses to Swimsuits Part 2: a pattern for bikini bottoms

  1. Jenny says:

    What a simply beautiful process to make these Retro bikini bottoms.
    I also like the choice of material used as I love poka dots myself.
    I really like the high waist as well. Keeps things in their place.
    Think I’ll make a pair over the winter ready for my summer holiday.

  2. jo says:

    Would this pattern work with cotton, i am not using a stretchy synthetic but just a poplin, and am not sure if this will work…?

    • naomi says:

      The pattern as is really needs a stretchy fabric. If you want to make something similar in cotton, you’ll need to make it larger, so the measurements of the finished garment are about an inch larger than the person who’s going to wear it, and add a closure (like a zipper) to get into it.

  3. Miss Me says:

    I really like the Gathered Bikini suit. And I love the retro style but is there a way that I can make the waist for the bottoms lower?

  4. Anna says:

    So cute! PLEASE, any idea where I can find swim fabric similar to this shown? I have looked all over the internet and at my local fabric store to no avail, and I have been so excited to try and sew a swimsuit. I am specifically looking for a red checked fabric. (But polka dots would work too, I suppose!) Any direction would be much appreciated!
    ~Anna

  5. Jenny says:

    What seam allowance did you use for the pattern?

    • Naomi says:

      1/2″, but it’s pretty forgiving – if you’re used to sewing at 5/8″ just do that, it won’t make any difference.

  6. Amanda says:

    If using custom measurements would you reduce the length from waist to crotch by a percentage still? I often find swimsuits to be too short in this area for me and am nervous to not have the look I want if I reduce it…

    • Naomi says:

      No, you don’t want to reduce the vertical measurement like you do the horizontal. It’s a good idea to take an inch off the vertical measurement, just to make sure everything fits snuggly, but definitely not a large percentage like you do in the horizontal direction.

  7. beth says:

    How did you come to the measurement for the length between the leg holes? Did you just find the difference between the bottom measurement and the thigh measurements?

    • Naomi says:

      You want it to be 2 to 3 inches after it’s hemmed. If it’s much more it’ll bunch up weirdly against your legs and less just won’t cover everything you expect a swimsuit to. If the difference between the bottom and thigh measurements doesn’t line up, adjust the angle of the side seams a bit. And remember, the swimsuit is stretchy so the measurements don’t have to be perfect.

  8. Lauren says:

    I recently purchased a pair of high-waisted shorts (which fit very snug – for pants, anyway) that have a perfect fit and was wondering if I could use them as a pattern? I would, per your advice, reduce the size from side-to-side, and perhaps slightly modify the leg opening (but they’re pretty short so it might be okay)….other than that, can you think of anything else that might need to be modified?
    Also, I noticed that my store-bought (from Wal-Mart!) bikini bottoms have been made with two layers of spandex – is this preferable?
    Thank you so much for this post – I love the idea of making (or customizing) my own patterns!

    • Naomi says:

      Sure, you could use your shorts as a guide. Most swimsuits are made with only one layer. Some designs work better with a full lining, so that might be what’s going on with your old swimsuit, or it might have been particularly thin fabric that needed to be doubled so you can’t see through it.

      • Lauren says:

        Thank you!
        One more question: should the grain of the fabric go side-to-side or top-to-bottom….or does it matter?

        • Naomi says:

          Top to bottom. The stretchier direction should be side to side. On the right side of your fabric you should see vertical lines in the weave of the fabric and on the wrong side fainter horizontal lines.

  9. Kim Baker says:

    Thank you for this great idea! Sometimes it’s just better to do it yourself than to buy something that doesn’t fit the way you would want it to! And, I like the polka dot a lot :)

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