Recycling an old jacket to sew a practical DIY gym bag (or pool bag, like mine) will save you time AND money, since you’ll be able to reuse a few features already included in most of the jackets, instead of sewing them from scratch.

Notes on making a DIY gym bag

This is a long-ish tutorial but it’s not difficult to sew a gym bag — I promise! I just wanted this project to be suitable for beginners too, so I’ve included so many little tips that will hopefully help you diy a gym bag!
In all likelihood your piece of clothing won’t be exactly the same as mine: before you start cutting it apart, decide which features you want to save and include in your project.
If you don’t have an old jacket to use, you can use regular fabric. I would try with canvas or maybe denim for this project, which have a nice body so you can leave out any interfacing or linings, making this project faster.
You will also need a zipper if you aren’t recycling a jacket, and some 1″ nylon webbing to skip the straps creation. This way you’ll skip the pockets and wet bag, unless you want to create your own, instead of re-purposing them.

How to sew a gym bag

Materials:

Zippered and hooded winter jacket (or canvas and zipper), approx size L (menswear)
Seam ripper
Basic sewing tools and notions
Screwdriver
Quilt rulers (optional, but really useful)
Walking foot (optional but great when sewing on multiple layers of fabric)
Serger (optional, but great for finishing seams)

Included measurements (on both imperial and metrics, for your convenience) will give you a gym bag/pool bag exactly like mine, but they’re not set in stone: customize your own gym bag’s measurements to get the most out of your old jacket: this is refashion, and you’re the designer!

Just keep in mind to add seam allowances to custom measurements: I suggest 1/2″ (1.2 cm) seam allowances on every seam.

I will guide you through all the steps but I’m listing here all the various pieces measurements you’re going to need (all including 1/2″ seam allowances, where needed):

<Body of the bag: 17″ x 28″ (43 x 71 cm) CUT 1
Zipper: 17″ (43 cm) long approx NEED 1
Zipper tabs: 2 3/8″ x 4 3/4″ (6 x 12 cm) CUT 2
Side circles: radius = 4 1/2″ (11.5 cm) CUT 2
Pockets: reuse existing pockets, mine were approx 8″ x 8″ (20 x 20 cm)
Strap: 106-118″ x 3 3/4″ (270-300 x 9.5 cm) (CUT 1, by piecing together multiple strips of fabric)
Wet bag/shoe bag: one water-resistant hood needed

Warning: before you start cutting your jacket apart, take an overall look to evaluate if you have enough fabric. Below we share pattern piece instructions.

Body of the bag

Measure the back of the jacket, to determine the overall size of your bag.

Make sure you are measuring a regular rectangle by measuring the horizontal widest part at the cross back height and not at the hem, which is wider and the height at center back, excluding the hem portion.

Subtract from these values two times the seam allowances, on each direction (horizontal and vertical).

Mine was 17 x 28″ (43 x 71 cm), subtracting 1″ from each measurement I ended with a finished body bag piece of 16″ x 27″ (40.5 x 67.5 cm).

Zipper

Check that your jacket has a perfectly working heavy-duty plastic zipper, long approximately as your body of the bag shorter measurement (mine was 17″ = 43 cm): it’s ok if it is longer, I’ll show you in a minute how to shorten it.

My jacket front zipper length was longer than this, so I went on making it shorter: this is how to do that.

To shorten the zipper:

You will need scissors (not your best ones, for fabric only) and a little screwdriver. To remove the zipper teeth you need to push with your screwdriver’s blade at the base of each tooth: it’s that easy!

The top half of each one will tear off, then you will easily remove the bottom half of each one, using your hands. Metallic zipper ends can be removed and set aside, to be reused to shorten another zipper, while teeth can be thrown out.

Since mine was an open-end zipper, I had to remove teeth on both ends, to reduce bulk. To determine the length of your zipper lay it next to the body of the bag piece and leave 1/2″ (1.2cm) approximately on each end free from teeth.

When you’re done, bar tack the free tape on each end. Before you move on, double check the zipper is perfectly closing and opening, by pulling the slider completely up and down a couple of times.

Zipper tabs

For a nice-looking professional zipper end, cover its ends with a little fabric rectangle on each end.

Fold one of the zipper tab in half lengthwise, wrong sides together, aligning the raw edges. Fold in one of the raw edges to touch the center crease, finger press and repeat with the other raw edge. Close again along the first fold. Repeat all the steps for the other zipper tab.

Slip in one zipper end in one of the zipper tabs; topstitch back and forth a couple of times right on the crease. Repeat for the other end of the zipper.

Side circles

To determine the radius of the side circles, divide half of the longer finished dimension of the body of the bag rectangle by 3.14 (also known as pi Greco), then add 1″ for two seam allowances.

In my bag: 28″/2/3.14 = 4 1/2″

Tip: Did you know that you can use your Google URL bar to calculate anything? just write your numbers and your mathematical symbols and press “enter”… easy peasy!

You should be able to cut those two circles from the sleeve caps: check you have room enough there!

Fold the fabric in four and mark an arc, measuring the radius and pivoting at the folded corner. Cut along these marks, open the folds and you get a circle. Repeat for the other one.

Strap

Strap length

Finished measurement for the strap for a gym bag like mine should be something something between 106 and 118 ” (270-300 cm).

If using your own dimensions, use two times the longest dimension of the rectangle + 2 times the hanging straps that will form the handles to decide length.

Strap width

To reduce bulk and fabric needs, I will do a two-fold straps, serged along one edge. Using a wide and short 3-thread overlock will grant nice coverage.

If you decide for a three-fold regular strap (like these), you will need to recalculate the fabric you need.

Strap construction

For a 2-fold strap you need a long rectangle, 106-118″ x 3 3/4″ (270-300 x 9.5 cm); to do so, get the jacket sleeves, draw a line parallel to the grainline, in the middle and measure parallel lines on each side, 3 3/4″(9.5 cm) far from it.

Sum each rectangular piece length to determine the total length, taking account of 1″ (2.5 cm) seam allowances for each strip (1/2″ for each end).

Men’s Jacket – straps from sleeves” width=”700″ height=”469″ class=” size-full wp-image-194959 alignnone” />

Sure about having enough fabric? Start cutting out all of the pieces!

Sew them all together in one only long strap, aligning short raw edges right sides together, using 1/2″ (1.2 cm) seam allowance. Press seams open.Finish one long edge using a wide and short 3-thread overlock, which is decorative and will keep the fabric from raveling.

Start folding lengthwise the strap, tucking in the long raw edge and leaving the just-serged edge exposed. Finished width will become 1/3 of the original strip of fabric (1 1/4″ = 3.2 cm approximately). To keep consistent that width all the way through, visually help yourself by sticking two strips of painter’s tape on your sewing table, one 1 1/4″ apart from the other.

Go on folding and pinning for all the strip length. Close it in a loop, making sure it’s not twisted, and sew right sides together the two short edges still raw.

Press the seam open, then fold in thirds the last portion, just as you did before. Press the whole strap to crease.

Topstitch the strap along the center (help yourself going straight by placing another strip of painter’s tape stuck to your sewing machine, at the right distance):

Pockets

My jacket had fun and clever patch pockets, which included a zipper pocket on top. Originally they were attached to the jacket so they had a side opening, for hands; in my bag I decided to leave a top opening to be used as an “invisible pocket” where you can put your gym card or something else.

To enhance the trompe l’oeil (optical illusion), topstitch the top edge on the pocket only, before you attach it to the body of the bag; the bottom will be then topstitched in place.

To decide the placement, fold in half both the pockets and the body of the bag and mark with chalk.

Align these marks, moving down a couple of inches from the body of the bag top raw edge and stitch them together along the side and bottom edges of the pocket.

Note: On the sides, one row of stitching will be more than enough: the strap will be sewn into the pocket, later.

Repeat on the other side, with the other pocket; make sure they’re aligned!

Attach the straps

Mark the strap in quarters by folding it in half (put a pin on each end) and in half again (two more pins on these folds).

Place the strap so two opposite quarter marks match the center of the body of the bag, on its longer dimension. Pin the strap to the body of the bag, keeping it aligned with the pockets and covering their sides.

Tip: Before you start sewing, double check that strap is not twisted and that handles have the same length!

Topstitch the strap in place on both sides, using a walking foot if you have one. Go slowly and use your hand wheel if you feel your sewing machine is having a hard time sewing through all those layers.

Start and stop right above the pockets and stitch a square with an X through it to add strength.

Now you can topstitch each hanging portion of the handles, on both sides. I forgot about this step so this is why you don’t see the handles finished in the next pictures — sorry for the confusion!

Attaching the zipper exposed

Grab your zipper and mark its middle point and align it with the body of the bag center mark.

It doesn’t matter if your zipper tabs are a little over the body of the bag, you can clip them later, once it’s sewn together!

Now, flip the zipper over it so they are right sides together; align top edges. Pin, then sew, using a zipper foot

Press seam allowances toward the bag (they will hide over the zipper tape. Topstitch (I used a contrasting thread, just for fun).

To attach the other side of the zipper, fold up the body of the bag so it is right sides together with it.

This is how it looks when pinned to the free tape of the zipper:

Sew and press seam allowances toward the bag. You may find useful a point presser (did you know you can create your own? Here’s a pattern and tutorial for this!) to press the seam without creasing the fabric below.

Topstitch (contrasting thread for me, again) and this step is done!

Congrats, you’re almost done!

Adding the side circles

Mark quarters by clipping notches on both the side circles and on the body of the bag raw edges.

Turn your almost-bag inside out. Pin one of the side circles to one side of the body of the bag, right sides together matching notches.

Sew 1/2″ in from the raw edges and serge the seam allowances using again the 3-thread wide and short overlock stitch.

If you don’t have a serger, a great pro-quality way to finish this seam is the Hong Kong finish technique.

Repeat on the other side, but please make sure your zipper is open before you stitch them together, otherwise you won’t be able to turn your wonderful gym bag right side out!

Wet bag/shoe bag from a water-resistant hood (optional)

While this last step is totally optional, it upgrades this project to a whole new level: a useful extra in (literally) just a couple of seams more!

Lay the hood and fold it in half, matching the front opening, wrong sides together.

Sew along the neckline in one straight line; you may need to square up the seam at the front: just make sure you’re not touching the drawstring part.

Trim seam allowances to a scant 1/8″ (3 mm), then turn the hood/wet bag inside out, so right sides are now facing and enclosing the raw edges in. Push the corner out using a point turner.

Sew along the bottom edge using a 1/4″ (0.6 mm) seam allowance, turn right side out and congrats, you’re done!

Here’s your wet bag/ shoe bag filled with goodies: there’s plenty of room for anything you need to keep separated from the rest on your bag:

Let’s take a look at this bag! Here’s the tab detail: isn’t it so nice?

And here’s the bag filled with everything my daughter needs to go to her swimming lessons (included her Posh Robe, a free pattern you can download on my Craftsy designer page):

One more picture? Yes, please! Here’s the full bag, showing the pockets at their best:

Now it’s your turn: go to hubby’s closet and take out that old jacket…I want to see your creations!