What Does Seam Allowance Mean On A Sewing Pattern?

Are you wondering what seam allowance means on a sewing pattern?

Seam allowance can be a tricky thing to understand especially if you are just getting started with sewing. Knowing what is it, what it does and how to work with it is all part of sewing and you will be thankful you learnt now rather than later.

Whether you are making your own clothes or a quilt you will come across the term seam allowance and it is important to know and understand what it is. I started to learn about seam allowance when I was in my last 2 years of high school, I was doing textiles and loved sewing and making things.

I learnt there about fashion seam allowance but quickly learnt about costume industry seam allowance when I went onto university.

Each brand of sewing pattern, each person and each pattern will be different so it is key to knowing what to look for and what you need to add or not add in terms of seam allowance. This small part of sewing can really transform how you get started and boost your confidence along the way.

What Is Seam Allowance?

Seam allowance is the added width and measurement added to a pattern or garment. The seam allowance is the part in which you sew together the pattern pieces to create the garment.

Seam allowance is extra space that is added to a pattern or fabric when creating a garment or project. The added space then gives you the guidance to sew accurately the pieces together.

What Does Seam Allowance Mean On A Sewing Pattern?

The seam allowance on a pattern means that the pattern itself has seam allowance added. That essentially means you don’t have to add the seam allowance yourself.

Some patterns will have it included and some will require seam allowance adding. It will state the seam allowance in the instructions of the pattern.

What Does Seam Allowance Included Mean?

When a pattern states ‘seam allowance included’ this means that the seam allowance for that garment has already been put on the pattern.

That means you do not have to add your own to the pattern or mark onto fabric.

Make sure you know the depth of the seam allowance before sewing together the pieces.

If you sew over the allotted seam aloowance you would then be sewing into your garment space. Meaning you would be making your garment smaller and so the fit of the item wouldn’t be correct.

Is Seam Allowance On All Sewing Patterns?

Not all sewing patterns have the added seam allowance already on them. Some will require you to add your own sewing allowance while others will have incorporated it into the paper pattern.

The pattern itself will state on the instructions or front whether it has included seam allowance or not. Make sure to check this before cutting out a pattern or cutting out your fabric pieces.

How Do You Add Seam Allowance To A Pattern?

You can add seam allowance in a number of ways, either onto the paper pattern or onto the fabric as you trace around the pattern piece.

You can trace the pattern using a number of different tracing papers to get the outline shape and details needed such as notches and straight of grain lines.

Then you can add on around the edges your required seam allowance. Though I wouldn’t add too much as this can then create a problem keeping a consistent sewn line when joining the pieces together.

What Is The Standard Seam Allowance?

The standard seam allowance can range from 1/4 inch up to 1-inch depending on your project.

Most fashion garments and clothing patterns will use 1/4 inch upt o 5/8 of an inch.

Other projects such as bag making and soft toy patterns will use 5/8 inch.

While if you plan to make a costume to fit another person and will be needing to have fittings, it is often advised to use 1-inch seam allowance to give you plenty of room to work with.

Is Seam Allowance Important?

Yes, seam allowance is very important in making anything.

Always double check that your pattern either has seam allowance or doesn’t before you get started.

If you work without seam allowance you may notice your garment is smaller and tighter than expected and you may find the finished project to be slightly off in style and shape too.

How Do You Mark Seam Allowance On To Fabric?

You can mark seam allowance in a number of ways. One of the most popular is to lay the pattern pieces out onto the fabric as advised by the pattern instructions.

You then draw a solid line around the pattern as close and accurate as possible, like you are tracing it. You can do this using a fabric marking tool or piece of tailor’s chalk.

Then using a ruler or tape measure measure from the edge of the pattern piece outwards. Measure out your desired depth of seam allowance and mark with.

Carry on doing this all the way around your pattern pieces until you have a full border going around. This doesn’t have to be a solid line, just enough to create the shape and enough to follow when cutting out.

Where Do I Add Seam Allowance?

Seam allowance is required around every edge of the pattern piece, the seam allowance is essentially extra fabric to allow you to sew the pieces together so it would be required on each seam edge.

Seam allowance also needs to be on both sides of the seam to allow the fabric to be held together to create the line of the seam neatly and give the seam more strength.

Is There An Easy Way To Add Seam Allowance?

There is a simple and easy way to add seam allowance to any pattern. Whether you add this onto your paper pattern or onto your fabric it will work a treat.

Gather two pencil or two chalk liners for fabric and hold them together. Measure the depth from one point to the next. Make sure this is the depth you want you seam allowance to be.

For example if you want your seam allowance to be 1/4 inch, you want to make sure the gap from one point of the pencil to the next is 1/4 inch.

Put another pen/pencil or rubber in the middle to keep the gap secure and hold in place by placing a rubber band at the top and bottom.

Then use as you would a normal pencil, holding one to the edge of the pattern and the other on the outside. Draw along the edge of the pattern and at the same time you can be creating your second line for your seam allowance.

What Is The Average Seam Allowance?

This will differ depending on what type of project you are working on ie fashion clothing, costumes or toys and blankets.

The average is 1/4 of an inch on many different sewing platforms from fashion to home decor etc.

Costume and performance clothing will differer depending on the maker and the show. This is due to many companies will re-use costume pieces on multiple actors and performers or want to be able to expand them for another show.

So the more seam allowance in the costume the better use it can be for a later production. This also helps save money for shows if they can repurpose outfits and garments.

When Should I Clip Seam Allowances?

Seam allowances should only be clipped after the final fitting of the garment or once it is finished. If you are concealing the seams then you will need to clip them beforehand.

Seam allowances will only really need clipping if they are too bulky for the seam, have too many layers or are curved and need to relieve the strain in the seam and fabric.

If you are working with a fabric that may fray over time look at using a zig-zag stitch or overlocking to protect the seam from fraying over time.

How To Measure Seam Allowance On A Sewing Machine?

If you are wanting to create a nice even and neat seam you might be wondering how to measure seam allowance on your sewing machine.

There is a simple and easy way to do this. You can mark on your fabric before hand to follow the line or you can create a guide on your sewing machine.

I found using a piece of tape marked out at my designated seam allowance in place gave me an easy to follow guide when sewing. I would butt up my raw edge to the side of the tape and keep following that guide as I sewed.

This made my seams neater, more accurate and even. You can use a number of tapes or even use a band if you don’t want to use tape.

There are also guides on many sewing machines already that have the different seam allowances noted on the plate to the side where the feed dogs are.

How To Measure Seam Allowance?

You can measure seam allowance with a ruler, tape measure or by eye. Though if you are new to sewing I would suggest using a tape measure or ruler.

You can also get handy gadgets these days that are smaller and more accurate to use such as a sliding gauge or a flexible curved ruler.

How To Grade Seam Allowance?

Grading is a little more complex when it comes to seam allowance and not something I do often as I prefer to work on the fabric side of the garment not the paper side.

Grading is primarily for those who are very much in between sizes or wish to add or remove space on a certain part of the pattern. It is often in one of the main 3 areas: bust, waist or hips.

Grading seam allowance is fairly simple if you are knowledgable on grading patterns. Once you have graded your pattern to the fit and size you reguire you can do the seam with the seam allowance.

As you are following the outside line of your pattern piece you simply have to follow that line to allow for seam allowance.

How Much Seam Allowance For Binding?

Deciding how much seam allowance you require for binding depends on the project itself and how wide your seam allowance is on that project.

If your project has a seam allowance of 1/2 inch, you then need to create your binding with a seam allowance of 1/2 inch.

Be sure to remember with binding that you require seam allowance on both sides of the strip, not just one side.

How To Let Out A Garment With Seam Allowance?

If you are looking at how to let out a garment with seam allowance you will need to take note of how much seam allowance is there to start with.

Remember that you will need to allow both sides of the garment to be taken out to keep the garment symmetrical.

You can mark where you would like to take out your seam allowance before opening up the full seam. Open the seam between each mark and re-adjust.

Pin in place with the new seam and sew into place. Make sure you aren’t sewing too close to the raw edge as this can cause the seam to rip and fray and can often make the garment unrepairable.

How To Finish Seam Allowances?

There are a couple of ways in which you can finish your seam allowances. The most popular is to overlock the raw edges, whether together or individually.

If you don’t own an overlocker you can use the zig-zag settings on your sewing machine to create a similar effect to stop the raw edges from fraying.

You can also conceal the raw edges in a number of ways from french seams, binding or a felled seam. There are plenty more in which you can try to create a higher-end finish to your project.

What Does Turn In-Seam Allowance Mean?

A turn in seam allowance is a technique used to neated the raw edge of seam allowances. Mostly used in clothing it creates a nice neat edge on the inside and helps reduce the risk of frayed edges.

It is a way of simply folding the seam back under itself and sewing down the edge to hold it in place.

It is important to note that this second and third stitch line of the seam is not sewn onto the main body of the garment and is only visible on the inside.

I hope you have found this guide on sewing pattern seam allowance helpful and have found the answers to all your questions. If you have any further questions leave me a comment and I will be sure to help where I can!

Scroll to Top