Easy DIY Bench Seat Cushion (No Pro Skills Required!)
A bench seat cushion is the perfect finishing touch to add comfort, color, and style to a space - but custom cushions can be ridiculously expensive. When I built my bench seat built-ins, I knew I wanted a plush, tailored cushion, but the price of custom upholstery had me second-guessing. So, I decided to make my own bench seat cushion with box corners, and to my surprise, it was way easier than I expected!
If you’ve been wanting to upgrade a bench with a cozy, custom look, I’ll show you exactly how to sew a bench cushion step by step. No fancy sewing skills needed! And if you’re looking for more beginner-friendly home sewing ideas, be sure to check out my post on Easy Sewing Projects for Your Home. But first - let’s make that perfect cushion!
In This Article:
What you'll need to make A bench cushion
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- Upholstery Foam Cushion: I used 3 inch foam for comfort and to give my cushion a substantial look. Be sure to buy a piece of foam that is at least the length and depth of your bench. You can trim it down, so don't worry if it's too big when you buy it.
- Fabric of your choice: I used upholstery fabric with a bit of texture on my bench cushion. You will want to use a home decor fabric since it's a bit thicker and more durable.
- A sewing machine: this is my favorite, not too expensive and not too complicated machine.
- Needle and thread
- Measuring tape and ruler
- Scissors
- Electric knife or hack saw for cutting foam
Discover 3 Easy Steps To Design A Room That Both Looks Good AND Functions Well!
How To Sew A Bench Cushion: Step By Step Instructions
How to measure and cut your materials
Step 1: How to calculate fabric dimensions for seam allowances
- To find the length of your fabric: Take the length of your cushion + 1x the thickness of your foam. Example: my cushion length is 90.5 inches and my foam is 3 inches thick. So 90.5 + 3 = 93.5 inches long.
- To find the depth of your fabric: Take the depth of your foam + the thickness of your foam + 1 inch for the seam x 2. This allows the fabric to wrap around and gives you a seam in the back. Example: my cushion depth is 24.75 and my foam is 3 inches thick. So 24.75 + 3 + 1 = 28.75 inches x 2 = 57.5 inches.
Double-check your measurements before cutting, and remember - it's always better to cut slightly larger than too small!
Step 2: Tips for cutting bench foam without jagged edges
To size your upholstery foam correctly, start by measuring your bench. For the best fit, subtract about an inch from each side - this gives your bench seat cushion just the right amount of wiggle room.
- Lay your foam flat and use a marker to clearly mark the length.
- When it’s time to cut, grab an electric knife - the same kind you’d use to carve a holiday turkey. It might sound unusual, but trust me, it’s the easiest way to slice through foam while keeping a clean edge.
- No electric knife? A hacksaw works too! It takes a bit more effort, but it gets the job done.
- Once you’ve cut your foam to length, measure and mark the depth of your cushion.
- Use a straight edge to draw a cutting line, then follow it carefully with your electric knife or hacksaw for a precise, smooth finish.
Step 3: Dry fit the foam cushion on the bench
Once you've cut your foam, dry fit it on your bench to make sure it fits properly.
Step 4: Cut the fabric for your DIY bench cushion
Make sure you're working from a perfectly straight edge to measure your fabric correctly. You may need to cut your fabric to create a perfectly straight edge to start from.
- Once you have your straight edge, measure for the depth of your fabric and cut accordingly.
- Fold your fabric over in half length wise so that the good side of the fabric is facing in, then starting at one edge make a straight edge at one end. You may want to use binder clips or pins to hold your fabric in place, especially when working with a long piece.
- Measure for the length of your fabric from that end to the other end and cut.
How to attach fabric pieces and sew box corners for a polished look
Step 5: Sew down the edge of each end using a ½ inch seam
Step 6: Mark the folded edge
With a fabric marker, mark the folded edge of your cushion cover the entire length of your fabric.
Step 7: Prepare the seams for your box corners
- With the sewn fabric still good sides together, pinch the top layer of the fabric and pull it over until the sewn seam and the marked edge line up exactly.
- When doing this you'll create what looks like a new corner with your seam running diagonally from it.
- Place pins along your seam and through all layers of fabric to hold the seam to the marked edge on the opposite side.
Step 8: Measure for the box corners
- Slide a ruler down from the corner you just created until the inches indicated on your ruler (from one edge of your fabric to the other,) equal the thickness of your foam.
- Example: my foam is 3 inches thick. You can see in the image below that I slid my ruler down from the corner until there were three inches taken up on my ruler from one edge of the fabric to the other.
- With your fabric marker, draw a line along the edge of your ruler at this point.
Step 9: Sew along the line
- Sew along the line you made using a straight stitch.
- Cut the excess fabric off, leaving about ¼ an inch of excess fabric.
Step 10: Repeat steps 7-9 at the other end of your cushion cover
Step 11: Turn your cushion cover right side out
At this point you'll have what looks like a big envelope with one long edge open.
Assembling and finishing your DIY bench cushion
Now that your fabric is sewn and your bench foam is cut to size, it’s time to bring it all together!
Step 12: How to insert the bench foam and ensure a snug fit
- Starting at one end, hold the corner of one end of your foam and place as tightly against the inside box corner of your cushion cover as possible.
- Slide your foam into your cover and when you get to the other end, hold the corner of the foam and push/pull it as tightly into the other box corner as possible.
- This will take a bit of adjusting as you go. Be sure that the box corners are lined up with the corners of the foam and that the fabric on both sides of the foam are as even as possible.
Step 13: Sewing the final seam closed for a seamless, professional finish
Once you have your foam inside your cushion cover and it's adjusted the way you want it to fit, place it on your bench with the unfinished edge facing out.
- At one end of your cushion cover fold the short edge in so it lays flat against the foam - like you're wrapping a gift.
Step 14: Stitch the top flap down
- Fold the top flap down so everything lays flat and pin to hold in place.
- With a needle and thread stitch from the top of the diagonal seam to the bottom to hold the top flap down flat.
- Repeat step 13-14 at the other end of your cushion.
Step 15: Stitch the bottom flap
- Grab the bottom flap and fold the unfinished edge of fabric in about ½ an inch.
- Fold the bottom flap up and pin in place folding in the unfinished edge as you go.
- Continue the entire length of your cushion cover.
- Starting at one end with a needle and thread, stitch the entire length of your seam using a simple loop pattern.
- Once you've completed the seam turn your bench cushion over so that the stitched seam faces the back.
Want to take your cushion up a notch? Consider adding decorative details like piping for extra style and structure! And if you want to make your cushion removable, add a velcro closure like the kind I used for my duvet cover.
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Finishing And Caring For Your Bench Seat Cushion
Your new bench seat cushion is officially ready to shine! Just add your favorite decorative pillows to complete the look.
Whether it’s for a bench seat built-in in a modern sitting room or a bench seat in a cozy entryway, this custom cushion will instantly elevate the space.
To keep it looking fresh, give it a quick vacuum now and then to remove dust and lint. If you used a durable, upholstery-grade fabric, a damp cloth should handle most spills. And if you ever want to change up the look, consider making a second cushion in a different fabric for a quick seasonal refresh!
Final Thoughts: You Can Do It!
Sewing a bench seat cushion might seem intimidating at first, but once you break it down into simple steps, it’s totally doable - even if you’re not an expert with a sewing machine. Sewing your own home decor is a game-changer - affordable, customizable, and surprisingly fun!
Now that you’ve tackled a DIY bench cushion, why stop there? If you're looking for more easy ways to add personality to your space, check out my post on Easy Sewing Projects for Your Home. You’ll find simple, stylish ideas to level up your decor with fabric.
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