How to Transform Any Bag Pattern into a Stylish Backpack

One of the things I absolutely love about sewing is pattern modification. It never ceases to amaze me how even the simplest change can completely transform a design. A minor tweak here or a clever addition there, and you’ve created something entirely new. It’s one of my favourite ways to stretch creativity and get more from patterns.

I’ve wanted to turn the Stevie bag pattern into a cute backpack for the longest time. The idea was always in the back of my mind, but… life, right? My ever-growing “TO DO LIST” didn’t leave room for it. I kept telling myself, “One day, Monika,” but that day never seemed to come.

In recent months, many of you have asked if there is a way to make the Stevie bag without the binding. At first, I thought, “What a great idea!” Then it hit me: Why not kill two birds with one stone? (Or however the saying goes!) This way, I get my backpack, and you get an alternative sewing method for this pattern. Win-win! (More on the no-binding method in the future—stay tuned!)

In this post, I’ll show you how to hack your bag pattern into a backpack. While I’m using the Stevie bag as an example, the steps I’ll share can be applied to almost any bag pattern.

If you’d like to try out the Stevie Unisex Crossbody Bag Pattern for yourself, head over to the shop. It’s a versatile, stylish design that works perfectly as a crossbody and now, thanks to this hack, as a backpack too!

How to Modify a Crossbody Bag Pattern into a Backpack

Technically, we’re not modifying the original pattern for this hack. Instead, we’re adding shoulder straps with a back overlay and moving the strap connectors to give the bag its backpack functionality. This means you don’t need to alter any of the original pieces—perfect for keeping the option to make the bag a crossbody in the future!

You can use the strap connector template included in the pattern if you’d like, but I decided to try something a little different. I chose a triangle connector because I’ve used this style on the McFly Backpack before and love the look. Plus, I thought adding a pop of contrast with a different fabric would make an interesting detail.

You can follow the pattern instructions to assemble most of the bag. However, skip adding the strap connectors to the gusset since we’ll attach them to the back panel instead.

Making the Triangle Connector

To create your triangle connector, start with an 11 cm x 11 cm (4 1/4″ x 4 1/4″) sqare. Then, simply cut it diagonally to form two triangles. Easy, right? (This measurement already includes the seam allowance, so there is no need to add extra.)

If your fabric is lightweight, I recommend adding a layer of interfacing or stabiliser to your connectors. This will help them hold their shape, prevent sagging, and ensure they can withstand the weight of the backpack straps.

I used Decovil Light to stabilise my connectors. However, I only applied the stabiliser to half of the connector to reduce bulk. This method keeps the connectors strong where they need to bear the most weight while avoiding extra thickness in the seams. It’s a simple adjustment that makes a big difference!

You’ll need two strap adjusters and two D-rings or rectangle rings to make your straps adjustable and two webbing pieces, about 8 cm (3″) each, for the connectors. These smaller pieces will be attached to the triangle connectors and hold the D-rings (or rectangle rings), which the shoulder straps will thread through.

Sewing the Connectors

• Wrap the short webbing pieces around the D-rings (or rectangle rings) and baste the ends together to hold them in place.
• Take the triangle connectors and fold them in half, right sides together, along the diagonal edge. Insert the short webbing with the D-ring into the folded triangle, making sure the D-ring sits inside the fold.
• Sew along the diagonal edge to secure the webbing inside.
• Turn the triangle connector right side out. If you like, topstitch around all sides for a finished look or install a rivet in the centre for added durability.
• Take the external back panel and position the connectors along the side edges, just above the bottom curved corners. Baste them in place.

Creating the Back Overlay

You can design your template for the back overlay in any shape you like. But if you’d prefer to keep things simple, you can do what I did: use the Front Pocket (B) pattern piece from the Stevie bag pattern.

Here’s how I did it:

1. Measure 6 cm (2 3/8″) from the top edge of the Front Pocket (B) piece and draw a horizontal line.
2. Trace the top portion above this line to create your overlay template.

If you’re working with faux leather or another non-fraying material, you can skip adding a seam allowance and leave the edges raw for a clean finish. But if you’re using a woven cotton fabric, be sure to add a seam allowance, fold the edges under, and press them flat so there are no raw edges.

I suggest stabilising this piece with Decovil Light. A stabiliser will reinforce the fabric and help conceal the strap ends behind the overlay, resulting in a smoother, more professional-looking finish.

Making the Adjustable Shoulder Straps

You have two options for the shoulder straps: you can use webbing, like I did, or sew your own fabric straps. Both options work beautifully, so it’s really up to your preference and the look you’re going for.

I cut my webbing straps to 100 cm (40″) long each, but you can adjust the length to suit your needs. If you prefer shorter or longer straps, feel free to customise the length to make the backpack comfortable to wear.

Sewing the Shoulder Straps

• Take your long straps and feed one end through the strap adjusters, wrapping the strap around the middle bar. Fold under the edge and topstitch to secure it in place.

• Thread the loose strap ends through the D-rings, ten again through the strap adjusters, and pull them through.

• Decide on the position of the strap overlay (I measured 2.5 cm (1″) from the top edge of the back panel) and mark the placement.

• Move the overlay aside temporarily and position the loose strap ends on the back panel, ensuring they align with your marks. Stitch the webbing ends securely to the back panel.

Attaching the Overlay

• Place the overlay on top of the strap ends, ensuring it covers the raw edges. Stitch around all sides of the overlay to secure it to the back panel.
• Optional: For extra reinforcement, install a couple of rivets through each strap end. This will anchor them in place and add a decorative touch.

Finishing Your Project

With the connectors, straps, and overlay securely in place, you can finish sewing your bag according to the pattern instructions. When assembling the remaining pieces—particularly when attaching the gusset to the back panel—keep the straps and connectors out of the seams. Please take a moment to tuck them safely out of the way before stitching. This ensures a clean finish and prevents any accidental sewing that could affect the functionality or appearance of your bag.

Follow Along with My Step-by-Step YouTube Tutorial

Check out my step-by-step tutorial on YouTube for a more in-depth guide to this pattern hack! In the video, I walk you through every detail of the process—from preparing your connectors and straps to attaching them to your bag—so you can feel confident tackling this project.

Whether you’re a seasoned bag maker or trying a modification like this for the first time, the tutorial has tips and tricks to make the process easier. Watch it now and sew with me to create your stunning backpack!

I can’t wait to see your version of this backpack hack! If you try it, tag me on social media—I love seeing and sharing your fabulous makes with the sewing community. Your creativity always inspires me!

And don’t forget, there’s more to come! I’ll soon share a tutorial for an alternative construction method for this pattern that skips the binding. It’s a great option if you’re looking for a different way to assemble your bag. Stay tuned for that—it’s going to be a game-changer!

Happy sewing, and see you next time!

Stay crafty friend!