How to Sew an Upcycled Sweater Phone Bag: A Complete Tutorial for Your New Favorite Crossbody Purse
There is something quietly satisfying about turning an old sweater into something you actually use every day. Not a craft project that sits in a drawer, not a decoration that collects dust — but a real, functional crossbody cell phone purse that goes everywhere with you. This tutorial walks you through exactly how to make one, from choosing the right sweater to finishing the strap, and by the end you will have a soft, stretchy, one-of-a-kind phone bag that fits your lifestyle and costs almost nothing to make.
Whether you are new to sewing or have been at it for years, this upcycled sweater phone bag is an approachable project with results that look genuinely professional. It also happens to be one of the most satisfying ways to practice sustainable fashion at home.
Why Upcycle a Sweater Into a Phone Bag?
Before we get into the how, let’s talk about the why — because it matters more than you might think.
Every year, millions of sweaters end up in landfills or donation bins where they never get a second chance. A sweater with a small hole at the elbow, a slight snag, or a collar that has stretched out is still full of beautiful, usable fabric. The knit material is soft, has natural stretch, and is often made from wool, cotton, or a blend that holds up remarkably well to daily wear. When you turn that sweater into a crossbody phone purse, you are not just making something cute — you are keeping a piece of clothing out of the waste stream and giving it a purpose that could last for years.
Upcycled sewing projects like this one are also a fantastic entry point for anyone who wants to start sewing with intention. You are not investing in expensive fabric. You are not worrying about cutting perfectly on the grain. You are working with a forgiving material that already has character, and every imperfection becomes part of the charm.
What You Will Need
You do not need a lot of supplies for this project, which is part of what makes it so appealing. Here is what to gather before you start.
Materials:
One medium to large adult sweater — wool, cotton, acrylic, or a blend all work well. Look for one with a tight-enough knit that your phone won’t poke through but enough body to hold its shape. Thrift stores are the perfect source, and you can often find beautiful options for one or two dollars.
A piece of woven fabric for the lining, roughly a quarter yard. An old pillowcase, a cotton shirt, or quilting cotton all work beautifully. The lining gives the bag structure and prevents your phone from stretching the knit over time.
One magnetic snap closure or a zipper in a coordinating color. Magnetic snaps are beginner-friendly and give the bag a clean, polished look. A zipper adds security and is a great choice if you carry valuables.
Approximately one to one and a half yards of webbing, ribbon, or a repurposed bag strap for the crossbody strap. You can also cut a long strip from the sweater itself if it is a sturdy enough knit — more on that later.
A sewing machine, or if you prefer hand sewing, a sturdy needle and strong thread. Knit fabrics benefit from a stretch stitch or a narrow zigzag stitch on the machine. Hand sewers should use a backstitch for seams that will see stress.
Matching or contrasting thread, fabric scissors or a rotary cutter and mat, pins or clips, an iron and pressing cloth, and a seam ripper (just in case).
Optional but helpful:
Interfacing to add structure to the lining panels, a D-ring and swivel clip hardware if you want a detachable strap, and a ruler or seam gauge for measuring accurately.
Preparing Your Sweater
This step is where the magic begins. Lay your sweater flat on a clean surface and take a moment to appreciate what you are working with. Look at the color, the texture, the patterns if it has them. Think about which parts of the sweater are in the best condition and which panels would make the most visually interesting bag.
Start by washing and drying the sweater if you haven’t already. Wool sweaters may felt slightly in the wash, which is actually ideal for this project — felted wool doesn’t fray and is even more durable. If you want to encourage this, wash a wool sweater in hot water and dry it on high heat. For other fibers, follow the care label to avoid damage.
Once the sweater is clean and dry, press it gently with an iron on a low setting, using a pressing cloth to protect the fibers.
Now, cut the sweater apart at the seams. Use your seam ripper or small scissors to open the shoulder seams, side seams, and sleeves so that you end up with flat panels of fabric. This gives you the most cutting flexibility and lets you avoid any areas that are worn or damaged.
Lay your panels flat and take stock. You will typically get two large panels from the front and back of the body, plus two sleeves that can be used for straps, pockets, or small accent pieces.
Cutting Your Pieces
For a standard cell phone crossbody bag, here are the dimensions that work well for most phones, including larger ones with cases.
The outer bag panels (you will cut two, one for the front and one for the back) should each measure approximately 5.5 inches wide by 8 inches tall. This gives you room for seam allowances and results in a finished bag that comfortably fits most smartphones. If you have a particularly large phone or want extra room for a card or lip balm, size up to 6 inches wide by 9 inches tall.
For the lining, cut two panels from your woven fabric at the same dimensions as the outer panels.
If you are adding a pocket inside the bag, cut one additional piece of lining fabric at roughly 5 inches wide by 5 inches tall. This creates a shallow pocket that is perfect for a folded bill, a card, or your earbuds.
If you plan to use the sweater fabric for the strap, cut a long strip from one of the sleeves. Cut it approximately 3 inches wide and as long as possible. You will fold and sew this into a finished strap, so it needs to start wider than you want it to end up. Two strips sewn end to end can give you enough length for a full crossbody strap.
Sewing the Outer Bag
With your pieces cut, it is time to start sewing. Work in a well-lit space with your machine threaded and ready to go.
Begin with the outer panels. Place them right sides together and pin or clip along the sides and bottom. Using a narrow zigzag stitch or a stretch stitch set to medium length, sew along the sides and bottom with a half-inch seam allowance. Backstitch at the beginning and end of each seam to secure them.
If you would like a boxed bottom — which gives the bag a flat base so it stands up and holds its shape — pinch each bottom corner after sewing, aligning the side seam with the bottom seam to form a triangle point. Measure one inch from the tip of each triangle and draw a straight line across with a fabric pen. Sew along this line and then trim the triangle away, leaving a quarter-inch seam allowance beyond your stitching line. When you turn the bag right side out, you will see that the bottom now has a little flat dimension to it. This step is optional but makes the bag look and function beautifully.
Turn the outer bag right side out and press it gently, taking care not to stretch the knit. Set it aside.
Sewing the Lining
The lining process mirrors the outer bag with one additional step — installing the closure.
If you are using a magnetic snap, now is the time to attach it. On one of the lining panels, measure down about half an inch from the top center. This is where the female half of the magnetic snap will go. Follow the package instructions to attach it, using the small washers to reinforce the back of the fabric and prevent the snap from tearing through. Attach the male half of the snap to the second lining panel in the same position.
If you are adding an interior pocket, fold the pocket piece in half with right sides together so it becomes a piece roughly 5 inches wide and 2.5 inches tall. Sew across the top, leaving an opening in the middle for turning. Turn it right side out, press it flat, and topstitch across the top. Position it on one of the lining panels and sew it down around the three open sides with a small seam allowance.
Now sew the lining panels together the same way you sewed the outer bag — right sides together, sides and bottom, with the same seam allowance. Box the corners if you boxed them on the outer bag. Do not turn the lining right side out. Leave it wrong side out.
Assembling the Bag
This is the step that pulls everything together and feels incredibly satisfying.
With the outer bag turned right side out and the lining wrong side out, slide the lining inside the outer bag so that the right sides are facing each other. The lining sits inside the outer bag shell, and the raw edges at the top of both pieces should be aligned.
Pin all the way around the top opening, matching the side seams of the lining to the side seams of the outer bag. Sew around the entire top opening with a half-inch seam allowance, leaving a gap of about three inches somewhere along the back panel for turning.
Reach through the gap and pull the entire bag right side out through this opening. Gently push the lining down into the outer bag and use a pencil or chopstick to push out the corners. Press the top edge of the bag neatly, folding the raw edges of the turning gap inward and pressing them in line with the rest of the seam.
Topstitch all the way around the top opening of the bag, about an eighth to a quarter inch from the edge. This closes the turning gap and gives the bag a polished, finished look. This final topstitch is one of those small details that really elevates a handmade item.
Making and Attaching the Strap
The strap is what transforms this little pouch into a true crossbody phone bag, and you have several options depending on your style and the materials you have on hand.
If you are using the sweater fabric for the strap, take your long cut strip and fold it in thirds lengthwise, tucking the raw edges inside. Pin it along its length and sew close to the folded edge on both sides. This creates a finished tube of fabric that is sturdy and soft. Because knit fabric doesn’t fray, you don’t have to worry about the edges being perfectly enclosed — just make sure the strap is at least three quarters of an inch wide in its finished form so it doesn’t dig into your shoulder.
To determine strap length, hold one end at your shoulder and let the rest drape across your body to where you want the bag to sit. For most adults, a crossbody strap lands somewhere between 48 and 55 inches long when measured flat. Cut accordingly, keeping in mind that you will lose an inch or two to the attachment points.
If you are using webbing or ribbon, cut it to your desired length and finish the ends with a lighter flame (for synthetic webbing) or by folding and stitching (for ribbon or cotton straps).
To attach the strap directly, fold each end over by about an inch and pin it to the side seams of the bag, just below the topstitching at the top of the bag. Sew a small rectangle of stitching and then an X through the middle — this is the standard technique for attaching straps to bags and creates an extremely strong connection that will hold up to daily use.
If you want a more versatile bag, sew a D-ring into each side seam during assembly and use swivel clips on the ends of the strap so it is fully detachable. This also allows you to adjust the length if you buy adjustable slider hardware.
Finishing Touches and Customization
Now that your bag is assembled, step back and admire it — and then think about whether you want to add any final details.
Embroidery is a natural companion to sweater fabric and can add a monogram, a small floral motif, or any design you love to the front panel. Even simple running stitches in a contrasting thread color can make the bag feel intentional and custom.
Iron-on patches or hand-sewn appliqués are another easy way to add personality. A small embroidered patch over a minor flaw in the sweater fabric is a creative way to highlight the imperfection rather than hide it.
If your sweater had interesting details — a cable knit pattern, a Fair Isle band, a ribbed hem — try to position those elements on the front panel of the bag where they will be most visible. One of the joys of working with a found garment is that it brings its own design history with it.
Caring for Your Upcycled Phone Bag
Because the outer shell is knit fabric, your bag is best washed by hand in cool water with a gentle detergent. Lay it flat to dry. If the sweater was wool, treat it with the same care you would give any wool item — no hot water, no agitation, and no wringing.
Spot cleaning is your friend for everyday dirt. A damp cloth and a tiny drop of dish soap will handle most smudges. With a little care, your upcycled phone bag will last for years and continue to look better as it ages.
Why a Digital PDF Tutorial Makes Sense
If you have fallen in love with this project and want to make it again — or share it with a friend, a student, or a crafting group — a digital PDF tutorial is the perfect companion. A good sewing PDF includes precise measurements, step-by-step photographs or illustrations, cutting diagrams, and helpful tips that make the process smooth even if you set the project down for a week and come back to it.
A downloadable PDF also means you can print it and pin it to your sewing board, pull it up on a tablet without hunting through a browser, and keep it forever without worrying about a website going offline. It is a genuine resource you own rather than something you borrow.
Final Thoughts
Making an upcycled sweater phone bag is one of those projects that rewards you twice — once when you finish sewing it and feel that specific pride of having made something real, and again every time you use it. It is soft where other bags are stiff. It is free or nearly free when other bags cost forty dollars. It carries a story that a mass-produced item simply cannot.
If you have an old sweater you’ve been meaning to do something with, or if you just walked past the dollar bin at a thrift store and saw a gorgeous cable knit in exactly your color, this is your sign. Cut it up. Sew it together. Wear it everywhere.
Your phone bag is waiting.
