How to Sew YOUR size
Being a cosplayer is challenging for many reasons. Expense and flamboyant designs can be tough to deal with, but even if you go to that sketchy costume site to buy your costume there is one more challenge to face...sizing. As a tall and chubby woman, I’ve always found it nearly impossible to find my size. Even sewing patterns seem to have the problem of making “average” size ranges that don’t fit right. Anyway, the point of this tutorial is to teach you guys how to sew basic patterns to fit you!
NOTICE: If you like to buy sewing patterns and just adjust them to your size, that’s fine too!
Step 1: Break it down now, ya’ll!
The first step to any project is breaking down your outfit. I’ll be using my Litwick cosplay for this. I find it easiest to look at (or create) a reference, then draw it piece by piece on a separate paper. “Okay, so how do I know what is and isn’t a whole piece?” You don’t. Unless you find a very detailed character sheet, the number of pieces is completely up to you.
As you can see, I made views from the front and back. Colors and designs changed while I was sewing this cosplay, but such is art. Also, it really helps to look up similarly shaped clothing online to help you draw a flat of your clothing. Flats are exactly what they sound like, a 2D drawing of clothing. This is where you’ll lay down seams, buttons, and just get a general idea of the shapes you’ll cut out for your outfit.
Step 2: Shapes and Measurements
No matter what size it is, clothing will usually be made up of a few shapes. A size 4 shirt will be made of the exact same shapes as a size 26 shirt of the same type. With this information in mind, break down each article of clothing into basic shapes. The halter top on the top of my dress was made of stretch cotton with 4 shapes: collar, back left, back right, and front. I admit I altered this from a sewing pattern, but we’ll get patterns in a second.
The vertical lines with horizontal marks are seams. This isn’t necessarily a flat as much as it is a diagram, really.
Also, I live by measuring tape. It allows you to go around round objects (like literally anything on your body) without all the hard math! If you don’t have one, I advise either getting one or magically become capable of math. The rest of this tutorial uses measuring tape.
In the fashion world, there are basic areas for measurement. If you’ve ever gone to a tailor, these are the same areas they’ll measure on you to tailor your clothing. This picture will help you locate those areas.
Once you know your sizes and the shapes you’ll be making, you’re ready to start!
Step 3: Making your pattern
You have your reference, your flats, and your measurements. Time to mush them together and splatter them on some paper. I use wrapping paper with a grid pattern. Cheap, easy, maintains better than those cheap toilet paper-like sewing patterns from Joanns.
Always make a mock of your clothing with cheap material that’s similar to your costume fabric. Mock garments allow you to save good fabric and make alterations.
Patterns are actually a lot easier than they seem. If your neckline is supposed to go (comfortably) around your neck, measure your neck, divide by the amount of pieces you have. I had three pieces for the halter top. Because my front and back pieces were symmetrical, I just cut two pieces and split one down the middle. Why does that matter? It matters because it means I divided my neck circumference by two, then split it into three. If you measure the front piece both of the back pieces, it still adds up into the total of inches around your neck. If it doesn’t? Trim it down or re-math and re-cut.
For your bust and waist, take your bust and waist measurements and alter the shape to those measurements. Commit this to memory, you’ll use this technique for ALL of your measurements (or at least until you learn a more formal technique). Using a ruler, draw a vertical line on your paper that matches the length of your garment. Now create horizontal lines (starting from the middle number of your measurement i.e. 5 inches, line the vertical line up with 3) and draw a line matching the HALVED total of your neck. Measure from your neck to the center of your bust. Draw another horizontal line at the end. Next, use a ruler to draw the shape of your garment. I freehand curves and alter them as I go (HENCE THE MOCK MATERIAL). In general, though, it’s a better idea to use a curved ruler. The point is that you’ll want to hit every end point of your horizontal lines. Depending on your measurements and material, you may have a few curves in your originally straight, blocky, shape. That’s natural.
Now, the bust/waist/hip measurements are a bit...exaggerated, but I wanted to show that it’s perfectly fine to start with the small shape on the bottom and come out with a slightly curvy or straighter pattern.
Depending on your material and pattern, you might need to add darts to make a tighter fit. Darts are triangles or diamond shapes made on a pattern, that act as folds to make a garment more form fitting. You’ll want to test placement of your darts through your mock up. There’s a few places to place darts, but the places I’ve used them are: bust to armpit, stomach, and back.
Step 4: Sew and alter
If you’ve decided to make a mock first (as I so wisely advised) your next step is to sew your pieces together and alter them to fit better. Alterations could include: Adding or subtracting the size of your patterns, adding or releasing darts, planning for zippers/buttons/closures, etc. Once you’re happy with your mock garment, seam rip the pieces apart again and use them to alter your original pattern.
NEVER CHEAT YOURSELF QUALITY TO MAKE UP FOR LOST TIME. If you mess up and you have 3 days left until that convention just go without a costume! I know going to a con without a costume when you’ve worked so hard sounds heinous, but trust me, it’s better to make up for your mistake for a future con than to sew over it and pump something you’re not happy with out.
Ta-da! You have your own pattern to fit your body! Now you can sew up the real thing.
DIsclaimer: I am but a humble space slime. I cannot do more than simple math. I also admit that I have no formal training. This tutorial is how I taught myself to sew my own costumes. It took me years to perfect this technique. It’s a little long winded (probably a lot more steps and alterations than a pro would have), but I decided to put this out there for anyone who wanted to try their hand at sewing. Good luck you guys!
Pro tip:
The amount of pieces for the garment decide the size of which you cut them. If you have two pieces, a front and a back, divide your measurements by 2. If 4 pieces, divide by 4. ALWAYS ADD IN YOUR SEAM ALLOWANCE (.25 inches)
Pro tips:
If there’s belts and buttons galore on your costume (and you aren’t a COMPLETE perfectionist), just sew them down. Not every belt or button has to be functional.
More or less pieces depend on the effect you’re going for. If you have a few layers of shirts or jackets, it will save time (and you from heatstroke) if you just create the illusion that you’re wearing more than one piece of clothing. You could also create each piece and have that volume of multiple articles of clothing under that jacket. Your choice!


















