Hey there, creative folks! Do you have a pile of old t-shirts or maybe a polo shirt that’s seen better days? Don’t throw them out! What if I told you that you could turn those forgotten clothes into a super cool, comfy DIY racerback tank top? It’s true! Making your own clothes is not only fun, but it’s also a great way to save money and help our planet by upcycling.
I’m Catherine, your friendly sewing guide, and I absolutely love turning something old into something new and exciting. Today, we’re going to dive into how to make a DIY racerback tank top. Whether you’re starting with a basic tee or a collared polo, I’ll walk you through the steps. It might sound tricky, but I promise, with a little patience and some simple sewing, you’ll have a new favorite tank top in no time. So, grab your old shirts, and let’s get started on this fun sewing adventure!
Why Bother Making Your Own Racerback Tank?
You might be wondering, “Why make a DIY racerback tank top when I can just buy one?” Well, there are so many good reasons! First, it’s super satisfying. There’s a special kind of pride you feel when you wear something you made with your own hands. Second, it’s eco-friendly! Upcycling clothes means less waste in landfills. You’re giving an old shirt a brand new life. Third, you get a custom fit. Sometimes store-bought clothes just don’t fit right. When you make it yourself, you can tweak it to fit your body perfectly. Plus, you can choose any old t-shirt or polo shirt, making your new tank top truly unique!
Gathering Your Sewing Tools and Materials
Before we start snipping, let’s make sure you have everything you need. Don’t worry, you probably have most of these things already if you’ve done a bit of sewing.
| Item | Why You Need It |
|---|---|
| An old T-shirt or Polo | This will become your new DIY racerback tank top! |
| Sewing Machine | Makes sewing seams quick and neat. |
| Ballpoint/Stretch Needle | Special needle for knit fabrics (like t-shirts). |
| Fabric Scissors | Good sharp scissors make cutting easy. |
| Pins | To hold fabric pieces together before sewing. |
| Thread | Choose a color that matches or contrasts nicely. |
| Measuring Tape | For checking measurements. |
| Fabric Marker or Chalk | To draw your cutting lines. |
| Seam Ripper | For fixing any little mistakes (it happens!). |
| Iron and Ironing Board | Pressing seams makes your finished top look pro. |
| Optional: Serger | For a very neat edge finish, but not essential. |
| Optional: Another Tank Top | To use as a rough guide for shape if you like. |
Having these tools ready will make your DIY racerback tank top project go much smoother.
Getting Your Old Shirt Ready for Its Makeover

First things first, give your chosen shirt a good wash and a press with the iron. Starting with clean, smooth fabric makes cutting and sewing much easier. For this guide, we’ll look at two ways to create a DIY racerback tank top. One method is great for a smaller t-shirt that you want to make fit better, maybe by adding some fabric. The other is perfect for a larger polo shirt that you want to reshape.
Method 1: Upcycling a Small T-Shirt (The “Add-In & Drop-Down” Way)
Let’s say you have a t-shirt that’s a bit too small or the neckline is too high, like a kid’s t-shirt you want to make wearable. This method involves adding a bit of fabric (often from the sleeves you cut off) to the shoulder area to lower the armholes and neckline.
Step 1: Carefully Take Off the Sleeves and Open the Shoulders
Lay your t-shirt flat. Carefully cut off both sleeves right along the seam where they join the body of the shirt. Try to cut just the seam threads so you have the most fabric to work with from the sleeves. Next, if you want to drop the neckline and armholes, you’ll need to open up the shoulder seams. Use your seam ripper or carefully cut along the shoulder seam. If your t-shirt has a neckband you like, you can try to carefully remove it to reattach later. If not, don’t worry, we can finish the neck edge another way.
Step 2: Adding Fabric to the Shoulders
Now, take the sleeves you cut off. You can cut pieces from these sleeves to add into the shoulder area. This will make the armholes lower and can also help drop the neckline. Decide how much you want to drop it – maybe an inch or an inch and a half. Cut four identical pieces from your sleeve fabric to this desired width. Pin these new pieces between the front and back shoulder sections you opened up. It’s a good idea to baste these pieces in place first. Basting just means sewing with a long stitch length that’s easy to take out. This way, you can try on the t-shirt (carefully!) to see if you like where the armholes and neckline are sitting. If it’s too low, you can make the added pieces smaller. If it’s too high, you can make them bigger.
When you’re ready to sew them permanently, use a ballpoint needle in your sewing machine. This type of needle is best for knit fabrics because it slides between the fibers instead of piercing them, which prevents little holes or runs. Use a slight zigzag stitch (like width 1, length 2). This stitch will stretch with the fabric so your seams don’t pop!
Step 3: Shaping Your Racerback Armholes
Once you’re happy with the shoulder fit, it’s time to draw the racerback shape. Put the t-shirt on, preferably inside out. Look in a mirror and use your fabric marker or chalk to draw the armhole shape you want on the front. For the back, it can be tricky to draw on yourself! This is where a friend can be really helpful. If you’re on your own, do your best. Yoga skills might come in handy here! After drawing, take the t-shirt off. To make sure both armholes are the same, you can fold the t-shirt in half along the center, matching up the shoulders and side seams, and then cut along your drawn lines through both layers. Or, you can cut one armhole, then fold the shirt and use the cut side as a guide to cut the other. Remember to leave a little extra fabric for the seam allowance (the fabric that gets caught in the seam).
Step 4: Finishing the Neckline and Armholes
To finish the neckline, you can reattach the original neckband if you saved it. You’ll need to quarter-mark both the neckband and the neckline opening. This means folding them in half to find the center front and center back, and then folding again to find the side points. Match these marks and pin the band to the neckline, stretching the band slightly to fit between the pins. Sew it on with your slight zigzag stitch. For the armholes, you’ll create bands. You can cut strips of fabric, maybe from the leftover sleeve fabric or the bottom of another knit shirt if you have one. These strips should be about 1.5 inches wide. Measure your armhole opening. Your band should be a little bit shorter (maybe 1-2 inches) than the armhole so it pulls the edge in slightly and lies flat. Sew the short ends of each strip together to make a loop. Fold the loop in half lengthwise, wrong sides together, and press. Quarter-mark your armhole bands and the armholes themselves. Pin the band to the armhole, matching raw edges and quarter marks, gently stretching the band to fit. Sew it on. You can then trim any excess fabric close to the seam or finish the edge with a serger or a wider zigzag stitch. Press the band away from the t-shirt.
Voila! Your upcycled t-shirt is now a cool DIY racerback tank top!
Method 2: Transforming a Larger Polo Shirt into a Racerback
Got a polo shirt that’s too big or you just want to give it a new style? This method focuses on reshaping it.
Step 1: Trying On and Marking Your New Shape
Put the polo shirt on. If you have a racerback bra or another racerback tank you like, wear it underneath to help guide your new armhole shape. Using your fabric marker, draw the armhole lines you want. If the polo is much too big, pin out the excess fabric along the sides and shoulders until you like the fit. Don’t be afraid to get rid of that polo collar if you want a more traditional tank top neckline, or you can keep it for a unique look!
Step 2: Cutting and Initial Basting
Take the polo off. If you pinned it, you can mark along your pin lines before removing the pins. Carefully cut along your drawn lines for the armholes and any new side seams, remembering to leave a seam allowance. If you’ve changed the side seams, baste them together first using a long stitch. Try the polo on again (inside out is good for checking fit). This is your chance to make small adjustments. Is it too tight? Too loose? Are the armholes comfortable?
Step 3: Refining the Fit
Once you’re happy with the general shape, you can permanently sew your side seams using that trusty slight zigzag stitch and your ballpoint needle. Sometimes, even after shaping the armholes, you might have a bit of gaping, especially at the back or near the bust. You can often fix this by taking tiny “pinches” or small darts in existing seams, like if your polo has raglan sleeves (those diagonal shoulder seams). Just a small pinch, sewn down, can make a big difference.
Step 4: Finishing the Armholes (The “Hidden Band” Way)
For polo shirts, a nice way to finish the armholes is with a band that gets turned completely to the inside, so it doesn’t show from the outside. Cut strips of knit fabric (again, about 1.5 inches wide, and a bit shorter than your armhole measurement). This time, you don’t fold the band in half lengthwise. With right sides of the fabric together, pin and sew one raw edge of your single-layer band to the raw edge of the armhole, stretching the band gently to fit. Now, here’s a neat trick called understitching. Press the seam allowance (the little bit of fabric inside the seam) AND the band away from the main body of the tank top. Then, stitch very close to the seam line, on the band side, catching the seam allowance underneath. This helps the band roll to the inside neatly and stay hidden. After understitching, turn the band to the inside of the tank top. The understitching will make it want to fold right on the seam line. Press it flat. Then, topstitch from the right side of the tank top, about 1/2 inch or 5/8 inch from the edge, catching the free edge of the band on the inside. This creates a clean, professional-looking armhole.
Step 5: Hemming Your New Tank
Finally, if you cut the bottom of your polo shirt, you’ll need to hem it. Just fold the raw edge up towards the inside (maybe by a thumb’s width or about 1 inch), press, and then stitch it down using your slight zigzag stitch. If your polo was already a good length, you might be able to skip this!
And there you have it – a stylish DIY racerback tank top made from an old polo!
| Basic Steps Summary | T-Shirt Upcycle (Method 1) | Polo Shirt Upcycle (Method 2) |
|---|---|---|
| Preparation | Wash, iron. Remove sleeves, open shoulders. | Wash, iron. Try on, mark new shape. |
| Key Alteration | Add fabric at shoulders to drop armholes/neck. | Cut new armholes, reshape sides if needed. |
| Armhole Shaping | Draw and cut racerback shape. | Draw and cut racerback shape. |
| Neckline Finish | Reattach original band or create new one. | May keep collar or cut new neckline & finish with band/facing. |
| Armhole Finish | Visible band, folded and attached. | Hidden band, understitched and topstitched. |
| Seam Stitching | Slight zigzag with ballpoint needle. | Slight zigzag with ballpoint needle. |
| Final Touches | Press all seams. | Press all seams, hem if needed. |
Quick Tips for Sewing Knit Fabrics

Working with knit fabrics (like t-shirts and most polos) is easy once you know a few tricks for your DIY racerback tank top:
- Always use a ballpoint or stretch needle. This is key to avoid skipped stitches or damaging the fabric.
- Use a stretch stitch. A narrow zigzag, a lightning bolt stitch (if your machine has it), or a serger will allow your seams to stretch with the fabric.
- Don’t pull the fabric. Let your sewing machine’s feed dogs do the work of moving the fabric. Pulling can stretch it out of shape. The only time you stretch is when you’re attaching a band that’s slightly smaller than the opening.
- Press, don’t iron. Lift and press your iron rather than dragging it across knit fabric, which can also stretch it. Use a medium heat setting.
Look at Your Amazing New Tank Top!
Step back and admire your work! You’ve taken an old, perhaps unloved, shirt and transformed it into a fantastic, wearable DIY racerback tank top. How cool is that? You’ve learned some new skills, saved a shirt from the landfill, and created something totally unique.
This project is great because you can try it with different shirts and play around with the racerback shape. Maybe you want a very narrow racerback, or a wider one. It’s all up to you!
FAQs
How to turn a t-shirt into a racerback tank top?
First, you’ll cut off the sleeves. Then, you draw a racerback shape on the back. Cut along your lines. Finish the new armholes and neckline with fabric bands. It’s a fun way to change an old shirt!
How do you cut old T-shirts into workout tank tops?
You can cut off the sleeves for bigger armholes. You might also cut the neckline wider. Some people cut the sides open for a looser fit. Racerbacks are great for workouts too. Just shape the back like we talked about.
How do you change a shirt to a tank top?
The main step is removing the sleeves. Then you decide the new armhole shape. You might want to make them bigger. You can also change the neckline. Finish the raw edges so they look neat and don’t fray.
How to make a shirt into a tank top without cutting?
This is a bit tricky for a true tank top look! You could try folding the sleeves under and pinning them tightly. Or, you could gather the sleeves up onto the shoulder and secure them with a safety pin or a quick stitch. It won’t be a permanent tank top, but it can give a similar feel for a short time. For a real tank top, you usually need to cut.
How to cut large arm holes in T-shirts?
Start by taking off the sleeves. Then, try the shirt on. Look in a mirror. Draw how big you want the armholes to be. Make sure they are even on both sides. Cut carefully along your drawn lines. Remember, you can always cut more off, but you can’t add it back easily!
What Will You Upcycle Next?
Making a DIY racerback tank top is such a rewarding project. You get to be creative, practice your sewing skills, and end up with a piece of clothing you can be proud to wear. It shows that with a little imagination, old clothes can have an exciting new beginning.
So, go dig through your closet or head to a thrift store! Find those shirts that are just waiting for a second chance.


