To lengthen or shorten pants patterns, make the adjustment through the middle of the leg rather than simply adding to or cutting from the hem. This helps preserve the intended shape and circumference of the pant leg instead of accidentally making a flare wider or a tapered leg narrower.
In this guide, you’ll learn how to shorten and lengthen tapered and flared pants patterns, where to place adjustment lines, how to keep the grainline aligned, and when it can help to divide a larger adjustment between two areas of the leg. These are useful fitting skills to apply when working with pants sewing patterns from Winslet's before cutting your fabric.
Why Should You Avoid Adjusting Pants Length at the Hem?
Adjusting only at the hem can change the finished leg opening, sometimes quite dramatically. On flared pants, adding length at the bottom can increase the flare, while on tapered pants, extending the side seams downward can make the ankle opening too narrow.
Shortening directly from the hem can cause the opposite problem. A tapered leg may become less tapered because the new hem is positioned at a wider part of the pattern, while a flared leg can also end up with a wider bottom opening than intended.
For most length adjustments, make the change through the leg itself rather than at the bottom edge.
Where Should You Lengthen or Shorten a Pants Pattern?
The adjustment should usually be made through the middle of the pant leg, using horizontal lines drawn perpendicular to the grainline. For a larger adjustment, it can be useful to divide the change between two locations rather than putting all of it in one place.
A practical method is to place:
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One adjustment line through the thigh
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A second adjustment line around the calf
For a smaller alteration or a very straight-leg style, one adjustment line may be enough.
What Do You Need to Adjust Pants Length?
You only need a few basic patternmaking tools:
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Pants pattern pieces
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Pen or pencil
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Ruler
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Tape
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Extra paper if you are lengthening
The extra paper does not need to be a special patternmaking paper; any suitable paper you have available can be used.
How to Shorten a Tapered Pants Pattern
To shorten tapered pants, cut across the leg at one or two perpendicular adjustment lines, overlap the sections by the amount you want to remove, and keep the grainline continuous.
Step-by-Step: Shortening Tapered Pants
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Draw the first adjustment line through the thigh.
Use a ruler to draw a straight line across the pattern in the thigh area. -
Make the line perpendicular to the grainline.
The adjustment line should meet the grainline at a 90-degree angle. -
Draw a second adjustment line around the calf.
Again, keep it perpendicular to the grainline. -
Cut along both lines.
Separate the pant leg into sections. -
Mark the amount to shorten.
Draw a guideline showing how much length you want to remove at the first cut. -
Overlap the pattern sections.
Move the lower section upward until the cut edge reaches the guideline. -
Keep the grainlines aligned.
Make sure the grainline remains straight through both sections. -
Tape the overlap in place.
Secure the pattern once the amount and alignment are correct. -
Repeat at the second adjustment line.
Shorten the calf area in the same way if you are dividing the alteration between two locations. -
Smooth the pattern edges.
The overlapping sections may create small jagged areas. Redraw these into smooth lines without changing the important corners of the pattern. -
Add paper if needed.
Depending on the pant shape and the amount shortened, a small piece of paper may be needed to fill a gap before redrawing. -
Trim away the excess.
Cut along the newly smoothed pattern edges.
How to Shorten a Flared Pants Pattern
The shortening method is similar for flared pants, but the position of the knee is especially important because the narrowest section of the flare is usually intended to sit near the knee.
Before altering a flared pattern, measure from the waistband to your knee. This helps you decide how much of the adjustment should be made through the upper leg so the shaped part of the flare remains in the right area.
Step-by-Step: Shortening Flared Pants
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Check your waistband-to-knee measurement.
Use this measurement to help determine how much length to remove through the thigh area. -
Draw an adjustment line through the thigh.
Keep it perpendicular to the grainline. -
Draw a second line through the calf.
This line should also be perpendicular to the grainline. -
Cut along both lines.
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Mark the amount to shorten.
Draw a guideline at each adjustment area. -
Overlap the pattern pieces.
Move each section upward by the desired amount. -
Keep the grainline straight.
Check alignment before taping. -
Tape everything in place.
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Smooth the side and inseam edges.
Add paper if needed to fill any gaps, or redraw directly if the adjustment is small. -
Trim excess paper.
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Repeat the same adjustment on the back pattern piece.
How to Lengthen a Tapered Pants Pattern
To lengthen tapered pants, cut through the adjustment line, insert extra paper, separate the sections by the amount you want to add, and keep the grainline aligned.
Step-by-Step: Lengthening Tapered Pants
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Draw an adjustment line through the thigh.
Make it perpendicular to the grainline. -
Add a second line around the calf if needed.
For a larger adjustment, dividing the added length between two places can help maintain the leg shape. -
Cut along the adjustment line or lines.
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Place extra paper underneath.
Tape one pattern section to the paper. -
Extend the grainline across the added paper.
If your paper is transparent and has a usable grid, that can also help with alignment. -
Mark the amount to lengthen.
Measure down from the cut edge and draw a horizontal guide. -
Move the lower section downward.
Align its cut edge with the guide. -
Keep the grainline continuous.
Check that the lower section has not shifted sideways. -
Tape the section in place.
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Repeat at the second adjustment line if using one.
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Redraw the edges.
The original side and inseam lines may no longer connect smoothly, so draw a new continuous line. -
Trim away excess paper.
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Make the same changes to the back pants pattern.
Do You Always Need Two Adjustment Lines?
No. A straight-leg pattern or a small length adjustment may only need one alteration line through the middle of the leg. In the source method, adding only an inch or two could reasonably be handled with a single line.
Two adjustment points become more useful when:
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You are adding or removing a larger amount of length.
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The pant leg has more shaping.
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You need to preserve the relationship between the thigh, knee, calf, and hem.
How to Lengthen Flared Pants
Lengthening flared pants uses the same cut-and-spread method as tapered pants, but the knee position needs extra attention.
The narrow inner section of a flare is generally intended to sit near the knee, so measuring from the waistband to the knee helps you decide how much length should be added through the thigh before adding the rest lower down.
Step-by-Step: Lengthening Flared Pants
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Measure from the waistband to your knee.
Use this as a guide for maintaining the intended knee position. -
Draw one adjustment line through the thigh and another through the calf.
Keep both perpendicular to the grainline. -
Cut along the lines.
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Place extra paper behind the first cut.
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Use the grainline or a visible grid for alignment.
Keep the cut edge horizontal and the grainline vertical. -
Separate the sections by the amount you want to add.
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Tape the pattern in place.
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Repeat the process at the second adjustment point.
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Smooth the side and inseam lines.
The original edges may not meet cleanly once the sections are separated. -
Trim away excess paper or trace a clean new pattern piece.
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Repeat the same length adjustments on the back pattern.
Why Is the Grainline So Important?
The grainline keeps the pant leg sections vertically aligned after they are cut apart. If one section shifts sideways while you shorten or lengthen, the leg shape can become distorted.
Every horizontal adjustment line should be perpendicular to the grainline, and the grainline should stay continuous when the pattern sections are moved.
If you'd like to see the full process demonstrated visually, you can watch the video below.
Common Mistakes When Adjusting Pants Length
The most common problems come from altering at the hem, losing the grainline, or forgetting that shaped pant legs need their proportions preserved.
Adjusting Only at the Hem
Changing length at the hem can unintentionally alter the circumference. This is especially noticeable in tapered and flared pants.
Ignoring the Knee Position on Flared Pants
The narrow part of the flare should remain near the knee. Check your waistband-to-knee measurement before deciding how much length to add or remove through the upper leg.
Letting the Grainline Shift
Keep the grainline straight through every overlapped or separated section.
Leaving Jagged Edges
Length adjustments can interrupt the original side seam and inseam. Smooth these lines before using the pattern.
Changing Only the Front Pattern Piece
Any length adjustment made to the front pants pattern should also be made to the back pattern piece.
Adjust Pants Length Before Cutting Your Fabric
The best way to change pants length while preserving the original silhouette is to work through the leg rather than at the hem. Keep each adjustment line perpendicular to the grainline, divide larger changes between the thigh and calf when useful, smooth the pattern edges afterward, and always repeat the alteration on both the front and back pieces.
When you're ready to use these fitting skills on your next project, explore Winslet's sewing patterns collection and adjust the pattern length before moving on to fabric cutting.
FAQs
Where should I shorten pants on a sewing pattern?
Shorten through the middle of the pant leg rather than cutting the length from the hem. Draw the adjustment line perpendicular to the grainline, then overlap the pattern by the amount you want to remove.
Where should I lengthen pants on a sewing pattern?
Lengthen through the leg using one or two horizontal adjustment lines. Cut the pattern, insert extra paper, separate the sections by the required amount, and keep the grainline aligned.
Can I shorten pants from the hem?
You can, but it may change the hem circumference. A tapered leg can become wider at the bottom, and a flared leg may no longer keep its intended proportions.
Should I use one or two lengthen/shorten lines?
One line may be enough for a straight-leg style or a small adjustment. For a larger change or a more shaped pant leg, dividing the alteration between the thigh and calf can help preserve the design.
How do I adjust the length of flared pants?
Use the same cut-and-overlap or cut-and-spread method, but also check the waistband-to-knee measurement so the narrow part of the flare remains near the knee.
Do I need to adjust both front and back pants pieces?
Yes. Make the same amount of length adjustment to both the front and back pattern pieces so they continue to match during construction.
