Fun with Fit Part 3: horizontal pre-adjustments

Hello and welcome back to another Fun with Fit. After taking our body measurements and making our vertical pre- adjustments last time we should hopefully be beginning this session with a fitting shell that has it’s bustline , waist and hipline in the correct positions for our bodies. We are now going to use a similar approach to last week to try and get the horizontal measurements on the front and back of our pattern pieces to match closely to our bodies in some key areas. All of these pre- adjustments are working towards giving us a calico toile that is a great deal easier to tweak to perfection on the body than one sewn up straight from the pattern envelope.

Some of you may be lucky and have a bust, waist and hip measurement that all correlate to a butterick pattern size. I’m afraid that does not mean you can go and make a cup of tea and give this week a miss. We are not just working with full circumference measurements but instead are going to divide and conquer, treating the front of our body totally separately from the back. It is perfectly possible to have a pattern with the correct bust, waist or hip circumference that fits horribly both in front and back with side seams being pulled all over the place at strange angles. We are all very different proportions and will all need different amounts of room in different places.

To take our measurements this time we need a clear ‘side seam’ reference point on our body. Miss Dressform has tape pinned to mark her dividing line. An easy way to mark this on your body is by wearing a thin, stretchy vest and making sure the side seams are positioned perfectly equally between your front and back and in a nice straight vertical line. Then you can measure from side seam to side seam. For the lower body leggings with a side seam can be used or a tight stretch skirt as long as its not too bulky. Alternatively you could unhook your vest from your shoulders and pull it down and position it as if it is a mini skirt. If you happen to live in the UK Marks and Spencer sell appropriate vests in their lingerie section that only cost a few pounds. As with last week, wear well fitting, supportive undergarments and use elastic tied around your middle if you need a guide for where your waist is.

One other thing that may be useful to have to hand for today is a calculator as we need to take into account the wearing ease that is built into our Butterick (or other brand) Fitting Shell. Wearing ease is additional room on top of body measurements that is included in garments in certain areas to allow us to do handy things like breathe and sit down. We didn’t need to think about this with vertical measurements last week but this week we will need to divide this ease up and add it to our horizonatal body measurements in certain places.

So lets get measuring:

BUST POINT TO BUST POINT: Our first measurement is going to be from Bust Point to Bust Point, this is from nipple to nipple on the body. If your nipples are not where you may wish they were you can measure from the central point of the full part of your bust instead. We will building your block around these points so no point highlighting any droopiness that no-one needs know about 😉 Below you can see the bust points (buttons!) and the measurement (peach ribbon) marked on the dressform.

bp tp bp dressform

Once you have taken this measurement on yourself jot it down and then divide it in two. This is your bust point to centre front measurement which we can now compare to the same measurement on your fitting shell. As with last week, be very careful not to include the seam allowances in your measurements. Below you can see the measuring line marked on my fitting shell with an orange line. No ease is taken into account from BP to BP so no need to concern yourself with that here.

BP to CF pattern

As with the vertical adjustments we made last time we are going to slash and spread if our pattern measurement is smaller than our body’s or slash and overlap if the opposite is true. To do this draw a line parallel to your centre front line and apporxiamtely 3cm (1 inch) inside it. Cut down this line and spread or overlap the required amount. For a recap on the spreading or overlapping method have a glance at Fun with Fit part 2 where we covered this in more detail.

FRONT BUSTLINE: Once our bust point to centre-front measurement matches  our fitting shell pattern we are going to move on to our front bustline measurement. This is taken from side seam to side seam across the front of the body on the bust line. You can see this below on Miss Dressform (peach ribbon) and marked on my fitting shell pattern with a red line.

bustline front dressform



front bustline pattern

Any adjustment required is going to be made to the left hand side of our bust point as we already know that the distance between bust point (BP) and centre-front (CF) is correct. Before we compare measurements we need to once again divide our side seam to side seam body measurement in two so that we are working with our Centre Front to Side Seam measurement. Then in this case we need to add 1.8cm (3/4 inch) on to this as that is the amount of ease between CF and Side Seam on the Butterick Fitting Shell.

So to clarify:

Side seam to side seam on body divided by 2 + 1.8cm  (3/4 inch) ease  compared to Centre Front to Side Seam on pattern piece.

Draw a line parallel with your centre-front midway between your bust point and side seam and increase or reduce your pattern piece to match your body once again using the slash and spread or slash and overlap approach. Below you can see my bodice front pattern piece increased (spread) between Bust Point and Centre Front and decreased (overlapped) between Bust Point and side seam.

Pattern increased between Centre Front and Bust Point and decreased between Bust Point and Side Seam.
Pattern increased between Centre Front and Bust Point and decreased between Bust Point and Side Seam.

If you are concerned that your adjustments have interfered with the neckline or shoulder width do not be. We will be addressing and temporary changes like these directly on the calico toile once we try it on.


Next we are going to be working along the bustline again but this time on our back bodice. This time you only need to do the one measurement from side seam to side seam. Take this measurement on the body and divide it in 2 again to obtain the Centre Back to Side seam measurement. Once again you need to add 1.8cm (3/4 inch) to this number to accommodate the wearing ease included in the pattern.

Bustline Back on Dressform
Bustline Back on Dressform

Before you begin measuring and editing your pattern piece you need to mark your bustline on it. Measure from the Underarm point on your FRONT pattern side seam to your bustline which may well have been moved during our vertical adjustments made in the last session. Measure and mark this same distance on the side seam of your BACK pattern piece and draw a line at this height that is at a perfect right angle to the Centre Back. You can see this done on my back pattern piece below with a purple line.

back bustline
Back Bustline marked onto Bodice Back Pattern Piece

The adjustment to our Back Bustline will need to be performed a little differently to our other adjustments with the use of an L slash.  To do this draw a vertical line through the middle of the back shoulder dart down to your back bustline. Cut down and accross from shoulder to side seam. Then, keeping pattern level at the bustline move your pattern piece in or out just as if you were performing the slash and spread or slash and overlap adjustments we have done previously. Below is an example of the L slash having been done to increase this area.

L slash to increase Back Bustline.
L slash to increase Back Bustline.

If you need to increase the width here and slash and spread  you will end up with a bigger shoulder dart and will need to redraw the shoulder dart lines. You can see that I have done this in green pen on the image above. If you need to decrease the width in this area and  slash and overlap you will end up with a smaller shoulder dart or possibly eliminating it all together. You will also need to redraw your side seam so that it is a smooth straight line again after the adjustment, once again I have shown this done above with a green pen.

FRONT WAIST Next we are looking at the waist. Once again this adjustment will vary slightly from our slash and spread/overlap method but is very simple to do.

Start by taking your own front waist measure from side seam to side seam, you can see this demonstrated on Miss Dressform below. Jot down your measurement and as previously divide it in two to obtain your Centre Front to Side Seam measurement. Add 6mm (1/4 inch) to this number as this is the amount of ease included in this area on your pattern.

front waist dressform

When you come to measure the Centre Front to Side Seam on your pattern piece be sure not to include the dart allowance in your measurement. See below the areas you are measuring as marked by turquoise pen. Waist A and Waist B need to then be added together and this is your Centre Front to Side Seam pattern measurement.

Waist measurement pattern front
Waist measurement Pattern Front


For this adjustment we are simply going to add or subtract our difference at the side seam line. Make a clear mark on your pattern piece where your new front waist side seam needs to be. Draw in your new side seam from Bust dart to your new waist.

BACK WAIST Repeat this process for the back waist once again remembering to add the 6mm (1/4 inch) ease after dividing your body measurement in two and to not include the dart allowance when measuring your pattern piece. Mark where your new back waist side seam will need to go and draw in your new side seam from underarm to waist on your back bodice. You can see an example of a waist decrease on the Front Bodice and a waist increase on the Back Bodice below. I have also redrawn in the seam allowances and marked up the new seam allowances with purple dash lines.

front waist decreased back waist increased
Example of waist decrease on Front Bodice and waist increase on Back Bodice.


Obviously the waist size of our skirt needs to match that of our bodice seeing as these are going to be stitched together. Measure and mark a line to indicate the new side seam position of front and back waist on your skirt pattern pieces. As the skirt pieces have two darts rather than one you will need to measure and add togetehr three areas for each. You can see these areas marked in the photo below.  Just place your mark and do not do anything further as we are going to establish our hip side seam position first before redrawing our side seam line.

marks made to adjust waist and hips on skirt front


Front Hip measurement on Dressform
Front Hip measurement on Dressform

The hips need to be approached in the exact same was as the waist front and waist back, obviously you don’t have the inconvenience of the darts at hip level so that makes things a little more straightforward. Once again measure the body first from side seam to side seam, divide into two and then in the case of this area add 12.5mm (1/2 inch) ease to this number as 5cm (2 inches) ease has been added to the Butterick Pattern at hip level overall so this area needs to include one quarter of that amount. Just like with the waist mark your changes clearly on your pattern showing where your new hipline side seam needs to be, you can see this below (dark pink line).  This area can vary dramatically between front and back dependent on derriere size so it is a very important one to do!

marks made to adjust waist and hips on skirt front
Waist and hip positions marked on pattern piece

Using a French Curve, a Pattern Master or carefully by hand redraw your skirt side seams to join your new waist points to your new hip points. Cross out the old front and back curves so you don’t get confused later on.

New waist to hip curve drawn in and old one crossed out.
New waist to hip curve drawn in and old one crossed out.


One final thing we need to do today is to true up any discrepancy we may have in the length of our bodice side seams caused by our vertical adjustments from last week. To do this you need to do the following:

*Temporarily turn under seam allowance on BACK BODICE Side Seam.

*Lay BACK BODICE on top of FRONT BODICE along side seams matching the BACK BODICE BUSTLINE to the LOWER DART LEG of your FRONT BODICE. Pin in place. You can see this in the image below, the back bodice bustline (purple) matches the lower dart leg on the front bodice (green line)

Back bodice pinned to front at side seam
Back bodice pinned to front at side seam

*Draw in a new smooth waist curve that sits halfway between the current front waistline and back waistline. Shown with the black and red line in the image below:

line drawn to true waist
New waist line drawn in to make front and back side seams the sme length (red and black line)


*Make sure your new curve gets marked on both your front and back pattern piece.


Phew…so that’s it for this session folks! I hope that wasn’t all too laborious for you.

If possible iron your calico in advance of next week when we will be transferring markings, cutting out and sewing up our toiles!

Thanks for reading and have a great week.

14 responses to “Fun with Fit Part 3: horizontal pre-adjustments”

  1. Thanks for doing this, waiting for my shell pattern to arrive as I only noticed the post last week but appreciate your detailed tutorial. I am also glad to get advice from a seamstress who knows the challenges of petite ladies.

  2. Wow, this fitting information is extremely detailed and so, so helpful! Thank you ever so much for taking the time to write it all up ~ I know where I can come for the first stop with fitting problems. ❤


  3. Even though I’m not following along with this at the moment, I am dipping in to see what is going on. Thanks for all your hard work with this – I’m sure I will be coming back to it in the future when I get my dressmaking mojo back again (probably in the spring!)

  4. Thanks, Ami for putting all this effort into the fitting series.
    I can’t wait to read through them! I will sure be printing them out and saving them in my sewing library for reference.

  5. My pattern has just arrived and I can’t wait to get started. This is such helpful information Ami, thank you so much for the time you’ve taken with this series. Since having my 3 children my shape has changed – I’ve had real trouble fitting my narrow back to a less narrow front and my dresess tend to bulge between my shoulder blades. This is such a great project to do now before I start any spring garments. I’m also loving Miss Dressform – she’s a lovely model and is on my purchase wish list for 2015.

  6. Thank you so much Ami, this series is amazing. You have given so much detail information that has beaten any classes I have taken. I’m really enjoying your fitting method and feel I have gained a better view of sewing patterns. Can’t wait for your next fitting post.

  7. I just completed part 3!. I am such a novice that I am unsure if I followed the last set of instructions correctly regarding drawing the new waist line. Is the side seam on the back bodice which I am lining up with the front side seam my new waist increase seam. I increased on the back and deceased on the front.

    Also, I am really learning a lot about adjusting for ease in sewing from you. I am an avid knitter so it has been fun learning about it in sewing patterns. Is there an easy place to find the ease listing on the pattern? I found it under “first fitting”.

    Finally, I am looking forward to purchasing your new top pattern. I love the look of it in the different fabrics! Now that I have my measurements, should I be using
    these same instructions that you have taught us for all future patterns? Thank you again. It has been a great learning experience.

    • Hi Susan, yep the new back side seam to the new front side seam just as they will be once they are stitched together:)
      The ease will be listed on some patterns and not on others- sometimes you will get ‘finished garment measurents’ so you can work
      Out the ease included by comparing these to the body measurements from the same size.
      With regards to following this with other patterns I would definitely apply parts of it to certain patterns yep. With garments like the Emmeline tee you would need to do far less personal tweaking than with something as tailored to the body as this fitting shell. It’s always good to measure the pattern before picking sizes and working out the rough amount of ease you like for your personal fit as this is down to the individual and how we like to wear certain garments. Lots of people complain that the ‘big 4’ have too much ease in their patterns but I usually find them done as I hate things too snug so it’s all up to you 🙂
      hope this helps a little!

  8. Thank you so much for this, after 2 kids a ‘very long’ hiatus from sewing and having to face up to the reality I no longer can fit in the ‘standard fit range’ of most patterns (most I ever had to do before was take in a waist) this is exactly what I needed to stop making excuses, give me a kick in the right direction, dust of my sewing machine and finally get sewing again!!!

  9. Wow, this must have taken you ages to write, thank you so much. I have done pattern making/ fitting before, and it was not as detailed as this, so no wonder my attempts at a trouser suit still looked awful despite hours of work and very expensive wool. And that is the crucial thing, material is so expensive that you cant really afford to mess up, so your series should ensure that everyones garments are wearable, rather than shoved to the back of the wardrobe!! I particularly like your strict tone “no, dont go and make a cup of tea!”…..we will all be sitting up straight and following the rest of the series x x

  10. Great tutorial, excited to get a fitted sloper so that I can start creating some of my own patterns rather than having to buy the closest pattern to my idea and adjust it.

    Should the ease added to the hip area be 2 inchs rather than 1/4?

    Thanks again, Katie

  11. I am finding this tutorial really helpful. I have a 36f bust, with a short 14.5 back neck to waist measurement. I have tried to do the that but found a huge difference between front and back side seams. Just a question, ,in altering the width of the front why would you spread the pattern at the front measurement for bust point, i understood this would be a fixed measurement? Obviously ,I am missing something. So would I ,with my humongous breasts spread my shell to the left of the bust point mark and then redraw the shoulder length.
    Thanks again for all your hard work and efforts

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