Learn how to sew a seam by hand or machine with some scrap pieces of fabric before moving on to your sewing projects. Sewing a straight seam is one of the first things beginner sewers need to do and is used in making garments, home decor, and almost everything!
How to Sew a Seam by Machine
To sew a seam with a sewing machine you will need:
- 2 scraps of fabric. I like using 5 x 5 inch (12 x 12cm) pieces as they are easy to handle.
- Your sewing machine
- All-purpose sewing foot This is your regular straight stitching foot that comes with your machine. It is usually all-metal or half metal and half plastic. On most modern machines it will snap on but older machines may have a screw mechanism for attaching.
If you haven’t purchased your sewing supplies yet then read my article on beginner sewing kits on a budget to find out the best basics to start with.
Step 1 – Pin the Fabric
Pin your two pieces of fabric with the RIGHT sides together at the raw edge.
This means the right sides (correct sides or printed sides) will be facing each other. If you are using plain fabric it may not have a right or wrong side. Other fabrics will be faded at the back so it will be obvious which is the right and wrong sides.
I like to use the horizontal method of pinning as I find it faster to remove. This means the pins are placed vertically along the edge with the heads sticking out from the edge of the fabric. It is a personal preference which way you place the pins.
Once you get confident with sewing seams you will probably be able to sew a straight seam without pins.
An alternative to using pins is to hand baste the seam with an up and down running stitch. This will hold the fabric pieces in place without you having to worry about sewing over pins and breaking a needle.
Step 2 – Set the Seam Allowance
Refer to your pattern instructions to find out what your seam allowance is. This is the distance you will be sewing from the edge. Common seam allowances are ½ inch (12mm) or ⅝ inch (15mm).
If your pattern does not have a seam allowance (this is common for European patterns) you will need to add it yourself. Don’t worry, I have an entire article on seam allowances and how to add them. Read >> seam allowance
Place your fabric under the foot with the needle on the seam allowance line and hold the threads. You should start at least ¼ inch (6mm) from the edge so that the whole foot is on the fabric.
The reason you should hold the threads to the back is so they don’t get caught under the foot or in the machine. You will only be holding them to start and not the whole time you are sewing.
You don’t need to measure the seam allowance. Most machines will have markings on the metal plate or in front of the foot so you can align the edge of the fabric with the markings. On my machine, the measurements are in inches on the metal at the back and you can see the millimeters on the front plastic.
Step 3 – Backstitch
Set your stitch length to 2.5. This is a good average setting to test on your fabric and is good for sewing pants, cuffs, collars, and more. The width should be 0 since we are doing a straight stitch.
Still holding the threads, backstitch almost to the edge. This simply means you take a few stitches backward. There is normally a button on the front of your machine to go backward. When the button is pressed in it sews backward and when released it sews forward. Don’t go off the edge. Most likely, this backstitching will only be 3 or 4 stitches. This is enough.
How to Sew a Seam at the Ends – Back stitching will stop the ends from unraveling, making your seam much stronger under stress.
Step 4 – Stitch Forwards
Stop backstitching, then release the threads in your fingers and start stitching forwards. Start sewing forwards in a straight line along the stitching line of the seam allowance line. Use the guides in the needle plate to keep nice and straight.
Step 5 – Backstitch the End
Backstitch the end of the seam as well. Stop ¼ inch (6mm) from the edge, press the back button and take a few stitches backward.
To remove the fabric from the machine, lift the foot and make sure the needle is up. Pull the fabric out and cut the threads. If your needle is down, you can turn the handwheel on the side of the machine to slowly lift it up.
Step 6 – Press
Open up your piece, press, and there it is. A nice straight seam! Pressing for sewing is slightly different from your regular ironing. Instead of dragging the iron along the seam, press up and down with medium pressure.
Troubleshooting Sewing a Seam
If your stitches look loopy on the back or the front, it may be because the sewing machine tension of your machine is incorrect. Adjust it so the top and bottom threads are perfectly balanced.
Our lesson on how to sew a seam by machine is finished and now let’s get on to how to sew a seam by hand.
How to Sew a Seam – Different Types
How to Sew a Seam in Knits
Sewing knits with a machine is almost the same as for woven fabrics with one exception. Instead of using a straight stitch, it is better to use a narrow zig-zag stitch. The reason a zig-zag is better is that it will stretch with the fabric preventing stitches from popping.
Further reading – How to Sew Stretch Fabric
How to Sew a Seam with Curves and Corners
Sewing gentle curves are easily done by gently swinging the fabric around as you sew. It is best done in one motion with your machine on a slow-speed setting. If you don’t have speed settings, then put your foot down lightly to sew.
Sharper curves may result in you having to stop and lift the presser foot to release bunched-up fabric. Put the presser foot down and start sewing again. The sharper the curve the more times you will need to do this. For really tight curves you may need to use the handwheel to move the needle even more slowly.
Corners are easier to sew than curves. Stop at the curve, lift the presser foot, pivot, and put the foot back down again.
How to Sew a Seam – Specialty Seams
French seams are a specialty seam used on fine and sheer fabrics as well as items such as pillowcases that need to be extra durable to withstand repeated washes. It is most suitable for straight or gently curved seams. See how to raw edges of the seam are completely enclosed.
Filled seams are useful for thicker fabrics such as denim jeans where you need to hide the raw edges. A felled seam will look smooth on both the inside and outside.
More Specialty Seams
How to Sew a Seam by Hand
I have a longer article on how to hand stitch a seam, but here I will give you a rundown on the best 3 methods. How to sew a seam by hand can be done by using:
- Running Stitch
- Ladder Stitch (Invisible Stitch)
How to Sew a Seam by Hand Supplies
To sew a seam by hand you will need:
- FABRIC – 2 scraps of fabric.
- THREAD – The best type of thread to use is a polyester thread that is designed for general purposes.
- NEEDLES – Universal needles are general sewing needles suitable for a wide variety of fabrics. Choose a needle size appropriate to your fabric.
How to Sew a Seam by Hand with Running Stitch
Running stitch is a simple up and down stitch and if you are a complete beginner then this is going to be the best stitch for you to learn how to sew a seam. It is one of the most basic stitches.
Start by threading your needle with a double thread and knotting the end. If you have any trouble threading the needle read my article on how to thread a needle.
Piece through the fabric from the underside and take small up and down stitches. For sewing a seam your stitches should be no more than ¼ inch (6mm) apart. The smaller the stitches, the stronger your seam will be.
How to Sew a Seam by Hand with Backstitch
Once you have mastered the running stitch, you will want to upgrade to the backstitch. Backstitch is an extra-strong hand stitch suitable for hand-stitched seams. It is also a useful embroidery stitch for decorative sewing. Read the full tutorial on how to backstitch
Here is a video from the Treasurie YouTube channel on how to backstitch.
How to Sew a Seam with an Invisible Ladder Stitch
For seams that have split open and need repairing, a ladder stitch can create an invisible seam, particularly when stitched in a matching thread. This invisible stitch is handy for closing cushion seas and mending toys.
- Bring the needle up through the fold of the seam at (1). This will hide the knot inside.
- Cross to the other side of the seam and insert the needle along the fold from (2) to (3).
- Cross over again and insert the needle from (4) to (5) along the fold of the seam.
- You can see the ladder starting to appear. Gently pull tight and you will have an invisible seam. Even with the bright red contrasting thread you can hardly see the stitches. Smaller stitches will hold a stronger seam.
More Type of Seam Hand Stitches
Here are some more hand stitches that can be used for sewing seams.
How to Sew a Seam – The Next Step
After you have learned how to sew a seam the next step is to finish the seam to prevent the edges from fraying. One of the easiest ways to do this is to use pinking shears to cut the edge. This serrated edge will help lessen fraying. A serger can also be used and gives a professional-looking seam. If you don’t have a serger, a wide zigzag stitch is an easy alternative to a serged seam. Read my article on seam finishes for more easy techniques.
How to Sew a Seam – In Conclusion
Congratulations! You’ve sewn your first pieces and now know how to sew a seam. With a little practice, you will now be ready to tackle your first sewing project and your first straight seam. Go and have a practice on some scraps and tell me what you think. Any tips to help other beginners?