Most of us who sew women’s pants struggle to get a great fit. There are so many variables in the body and the pattern that it’s difficult to decide where to focus the fitting work when fitting pants properly.
Pattern Blocks, Not Always Perfect
Pattern blocks are often made from a set of standard measurements and sometimes made from our own measurements. In theory, it seems like they should be a perfect fit, every time. Sadly, that is not always the case.
A few ill-fitting areas are normal and can result from subtle differences in our individual bodies. However, this is also the reason why store-bought clothing doesn’t always fit us the way we’d like. No worries! I am going to arm you with the knowledge of how to make these simple pattern adjustments, you’ll be on our way to making awesome fitting pants! (or shorts)
Note: These techniques can be applied to pattern blocks, PDF sewing patterns, or any home sewing pattern.
Why fit muslins are so important…
Although it may seem like our pattern blocks should fit perfectly right off the bat, this is not always the case. This is why it is so important to always sew a fit muslin. After a fitting, we can determine what changes need to be made.
These top 5 common pattern adjustments can be applied to a pattern block to create a new, better-fitting block! This will help to ensure any future styles will fit just as well! Also, we can apply these changes to any PDF or home sewing pattern.
Of course, there are heaps more than 5 alterations. However, once you understand a few of them. . . You’ll have the knowledge and understanding of how to make more advanced pattern adjustments!
Create the Test Garment
A marked pants muslin is the basis of the fitting process. I'm going to show you how to make one that eliminates the guesswork.
Select a Slacks Pattern
I begin with an everyday slacks style. This style has a crotch seam that grazes the body; the pants gently define the body, with the fabric either falling straight from the buttocks or slightly cupping the buttocks. The leg is straight or somewhat tapered. This is a good design for working pants fit because it’s neither extremely tight nor does it include extra design ease.
I recommend eliminating design elements such as pockets, yokes, and extra seaming. Waist darts in front and back are the easiest shaping features to work with. Once fitted, this plain pants pattern works as a master pattern to which you can add pockets, interesting waist treatments, or additional creative seamlines.
Choose a size that gives you 1-1⁄2 inches to 2-1⁄2 inches above your fullest lower body circumference.
Evaluate the crotch curve
Most pattern companies offer patterns with steep back-crotch curves and short back-crotch extensions. The back-crotch extension is not long enough to accommodate the body’s depth from back to front. This crotch shape can lead to excess fabric under the buttocks. Bear in mind that once you’ve done your fitting, your pattern’s crotch curve is likely to look different from the starting pattern.
Establish reference lines
For visual references during fitting, draw lines on the pattern (these will be transferred to the muslin). On the front and back, divide the hemline in half and extend a grainline up from this point to the waist, parallel to the existing grainline.
Add three horizontal balance lines (HBLs): On the pants front pattern, place one line just above the crotch level, perpendicular to the grainline, and the other two parallel to and above it, at 3-inch intervals, as shown on the facing page. Then, “walk” the pants back pattern’s side seam along the corresponding front pattern seamline, and transfer the horizontal line levels at the seamline. Draw these lines on the back, perpendicular to the grainline. The lines will match at the sides seams on the sewn muslin.
Sew the muslin
Use a heavy muslin or a light-colored, stable, bottom-weight fabric such as chino or twill. Cut the pattern from this fabric, and transfer the grainlines, HBLs, and darts to the fabric’s right side. Sew the pants, leaving an opening in front with standard seam allowances. Mark the seamlines at the center front, and press under one seam allowance. Don’t sew the darts or install a zipper.
This is the sequence I follow when fitting pants. Some steps are self-explanatory; others will be covered in greater detail on the following pages.
● Position the waist and crotch. Pull the pants up so the crotch barely touches the body at the inseam intersection. Tie an elastic strip around the waist to secure the pants. Check that the side seams are appropriately positioned on your body. Fold the hem allowances to the inside so the pant legs hang straight, with no breaks at the feet.
● Distribute the waist ease. Pin the front opening closed, aligning the center-front seamlines. Smooth the fabric flat at center front and back, distributing excess ease near the dart markings and side seams.
● Level the HBLs as much as possible. It’s usually straightforward to level the front HBLs, going around to the side. From the side seam around the back, the HBLs may dip downward, indicating a fitting issue. Using a yard- or meter-stick, measure up from the floor to be sure the HBLs are level.
● Assess and fit the front. Evaluate the girth across the front, and take in or let out the pants to solve problems. See “Adjust the front” at right.
● Assess and fit the back. Use the HBLs and grainlines to tell you what fitting changes you need to make. See “Adjust the back” on the facing page.
● Fit the waist. Form and pin waist darts and adjust the side seams as needed to take up all excess ease at the waistline.
● Refine the fit. Recheck that the HBLs is level and, if necessary, bring them to a level position. Mark the waist placement along the elastic’s lower edge. Make pattern changes, sew a new mock-up, assess the fit again, and make any further fitting changes.
The Top Most Used Pant Alterations
What is a full thigh adjustment?
A full thigh adjustment is used when a pant is a bit too tight around the upper to mid-thigh. This adjustment will not alter the length of the rise, waist, or inseam length.
How to adjust the pattern…
First, determine the approximate measurement that the pant will need to be increased. Divide this measurement by 2 and this new measurement will be applied to the front and back equally. Make note of this number.
Now, draw a line from the crotch point, angling it slightly downward at approximately a 45° angle. Then following the grainline, continue the line down to the bottom of the pant.
Starting at the hem, cut along the line to, but not through the crotch point. You need to leave a little bit of the pattern connected at the crotch point to act as a hinge. Next, swing open the pattern to the measurement determined earlier.
You can use small rectangular paper scraps and tape to secure the pattern. Finally, retrace the pattern onto new pattern paper. Blend and true all of the curves and lines.
Why shorten the rise?
Shortening the rise pattern adjustment is used when the rise of the pant is too long. This might result in the pant fitting higher on the waist than desired. This adjustment will not affect the side seam or waist measurements.
How to adjust the pattern…
First, determine the approximate amount the crotch needs to be shortened. Divide the measurement by 2 and record this measurement. It will be applied to the front and the back equally.
Starting around the middle of the rise, draw a horizontal line to the side seam. Starting at the rise, slash across the pattern leaving a little bit of the pattern connected to be used as a hinge. Next, overlap the pattern according to the measurement recorded earlier. Secure pattern closed with tape.
Shorten crotch depth
Why shorten the crotch depth?
Shortening the crotch depth is used when there is excess fabric or bagging in the crotch. This adjustment will not alter the inseam length or the waist measurement.
How to adjust the pattern…
First, determine the amount of excess fabric in the crotch. Divide this measurement by two and record the number. It will be applied to the front and back equally.
Starting around the mid-rise, draw a horizontal line across the pattern. Cut all the way across the pattern and separate the top from the bottom. Next, overlap the two pieces according to the measurement determined earlier.
Secure pattern by taping it back together. Trace pattern onto new pattern paper. Blend and true all lines and curves.
Lengthen back rise
Why lengthen the back rise?
Lengthening the back rise is used when the center back seam is a little snug in or under the bum. This adjustment will not alter the inseam or side seam length.
How to adjust the pattern…
First, determine the amount the back rise should be lengthened. Record this measurement. Next, draw approximately three horizontal lines across the pattern. It’s best to draw one around the mid-rise, and one above and below.
Starting at the rise, cut across the pattern to but, not through the side seam. You will need to leave a little bit of the pattern attached at the side seam to use a hinge.
Spread open the pattern to the measurement recorded earlier. It is best to distribute this measurement equally between all three spreads.
You can use small rectangular paper scraps and tape to hold the pattern in place. Finally, retrace the pattern onto new pattern paper. Blend and true all curves and lines.
However, this is also the reason why store-bought clothing doesn’t always fit us the way we’d like. No worries! Once armed with the knowledge of how to make these simple pattern adjustments, we’ll be on our way to making awesome fitting pants! (or shorts)
Why adjust the waist measurement?
This pattern adjustment is used when the waist measurement needs to be increased. This adjustment will not alter the inseam or side seam lengths.
How to adjust the pattern…
First determine the amount the pattern needs to be increased. Divide measurement in half and record that number. The amount will be applied equally to the front and back pant.
Now, there are a few ways to make this adjustment. The first way to make this adjustment is to start at the mid-hip area, draw a line to the waist at approximately a 45° angle.
Starting at the waist, cut to but not through the pattern. You will need to leave a bit of the pattern attached at the side seam for pivoting.
Next, open the pattern to the amount determined earlier. Secure pattern in place by taping small rectangular pieces of paper in the opening.
The second way is to slash and spread from the top of the waist down (maybe use a dart if available).
For both alterations, retrace the pattern onto new pattern paper. Blend and true all lines and curves.
Pant Alteration Video
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Clothing Alteration Guides
Simple Tailoring & Alterations: Hems - Waistbands - Seams - Sleeves - Pockets - Cuffs - Darts - Tucks - Fastenings - Necklines - Linings
Illustrated Guide to Advanced Dressmaking & Alteration: Learn to Make & Alter Dresses, Skirts, Shirts, Slacks. Add Pockets, Frills, Buttons, Zippers & So Much More - Over 180 Images & Illustrations
The Complete Photo Guide to Perfect Fitting
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