The Savvy Sage of Sewing Stimulation

Pants – the Einsteinian Zone

Good grief – what in the world is Claire talking about now?!!!  This is my cute way to deal with some very confusing spots in altering around patterns….specifically an area that when you release a seam you are actually making it smaller, when you take up a seam you are actually making it bigger, which of course goes against all our natural thinking and the natural order of the universe, hence the Einsteinian Zone!

Specifically I refer to the area under the armhole, and the crotch seam in the pants.  Here’s what I mean by that (I’m going to use pants here but this applies for under the arm area too).

When you start altering that curve at the bottom of the crotch seam, when you take it in, you lengthen the crotch so that it is lower….like this:

Notice that the blue area is the new taken in seam, and the old green area represents the original seam area.  This means that we “took in” and made the seam bigger, but it really made the fit larger – it dropped the length of the crotch seam and made it bigger….a la NBA basketball pants:

These aren't shorts; it's a skirt!

OK – back to our pants….and the taking in and release of that lower part of the crotch seam.

Hopefully this will make it easier to understand.  See how the lower part of the crotch seam is colored?  That’s to show you how this seam changes.  The vertical (or Y axis) is pink and the horizontal (or X axis) is green….notice how the line at the bottom of the crotch changes colors.  This is to show how it changes from the Y to the X and back to the Y axises.  This is important in figuring out your alteration here.

If your pants are pulling because the crotch seam is too short, then you will have to take it in to lengthen and allow for more room.

If your pants are pulling because they are not wide enough through the thighs, then you will have to release the inseam and hip side seam to give you more room.

How do you tell the difference – FEEL.  Pay close attention to how the pants feel. This is hard cause we’ve been drilled by RTW not to “feel” anything wrong when there’s a lot wrong.  When you put your pants on, do you feel you need to hike them up to get them to meet your waist?….and when you do that horrible “smiley” wrinkle shows up?  That’s a clear sign that the crotch seam is too short and needs to be released at the bottom.


I know I made this sound complicated, and I didn’t mean to.  What I want to get across to you is that shaping this crotch seam is very important, but you do have to remember a number of things when you’re doing it.

Now here’s the good news….there is a shortcut method that you can use to alter this seam that will help you.  It will ONLY lengthen the seam, and it won’t fit it to your body.

Here’s an example.

This is a great method for lengthening the crotch without having to draw it up from scratch.  This makes the adjustment and takes into consideration the X & Y axises.


So why did I go through all that laborious explanation above?  Because although this slash and spread method above is very handy to know, it does not fit your crotch area completely.

Here’s what I mean:

This is a mock-up of my pants pattern.  If you remember in the first post about all the “hot spots” on my body….this takes care of them.

  1. This is the curve (and the accompanying darts) I make to adjust for my small waist.  I have to be careful here, cause my waist is out of proportion to my hips.  This makes my hips look really large if I’m not careful.  At the same time I have to seat the pants, they can’t be sliding up and down, because they aren’t at my waist, so it at least needs to be moderately snug on my waist.  This is my preference – yours may be something else.
  2. This is the alteration curve I make to the front of my crotch seam, which seems to slope very gently into the bottom of the crotch…there is a distinctive curve to it, or corner to it, but you’ll notice it doesn’t occur as a sharp corner.
  3. This is the alteration curve I have for my sagging but!!!  My back comes down pretty straight about 2″ off my waist, then immediately curves in to the depth of the crotch seam.
  4. I like my inseam to hit to the front of my crotch seam – I just do – it’s what’s comfy for me, and this is the alteration for that preference.

Now let me make something perfectly clear.  I’m very picky about my pants and when I do a pattern for my clients, I’m equally as picky.  I’m on their case a lot.  Same is true of my students, almost to the maddening point of getting ready to kill me, I will bug them with questions:  Does it feel to high?…too low? it tight here?…is it tight there?…is it too loose?…why? And then I got through and usually ask them the same dang questions again after they’ve made an alteration!

But these are the tweaks you can add to your pants pattern that will make them remarkably wonderful.  This doesn’t dealt with hang, seated or style of leg here, we’re just talking about the crotch cause it’s such an important part to fit.

When you get a decent fit on your pants, then you can really start tweaking your pattern.  After you have it tweaked, which may take about 4 or 5 pairs of pants from a pattern, then you have the all time great TNT pattern for eternity.  Yes, eternity.  Why?  Because amazingly enough when you gain or loose weight, your body shape remains the same….because of the genetics given to you, this determines your shape and your body will put on weight evenly around your body, not here or there, although it does seem to go on our butts first and then bust last, and loose bust first and butts last – – the very, VERY last!!!

So how come I’m so smart and know this?

My darling niece and muse!

Because I’ve done too many deb to wedding dress….deb when they are in their sophomore year (after the freshman 15) to their wedding (where they always loose weight before the big day!)

So the pattern you make and have today, will last you for the rest of your life.  You will have to expand it a little through the years. And always – if you expand the side seam leg, do equal amount in the inseam and crotch seam (slash and spread).  But basically your shape and the tweak of your crotch will remain the same.

This is exactly how my pattern (made by my teacher over 30 years ago) has worked for me as I’ve put on a few (a-hem…..ok maybe more than a few) pounds through the years!



  1. I have my wonderful tnt pants pattern thanks to your advice. I gained some weight, but I am still able to use it by just adding a little. I like my crotch high, so I didn’t really have to lengthen it. I do have a question about your hip to waist. I have a small waist in comparison to my hips and the hip is what I will call a shelf that quickly goes out to hip width, not a gradual curve. Obviously I don’t want to emphasize this area. I have issues keeping up a contour waistband and getting it to fit properly. What do you do for your waistband?

    • Nancy – it’s OK to put in a lot of darts. I do that around the side. The thing is that you want to keep them graduated. I usually put the longest one closest to center front and center back, and then as I graduate to the side the darts get shorter. This is not only to make it look better, but we are more curvier around the side/hip area than in the stomach and fanny area. Of course if you’re the opposite, then graduate it the opposite way. I just don’t like to see a short, long short grouping of darts – just graduate the length. And you’ll be surprised what a small little dart will do – having 3 on the left back, right back,, left front and right front, can ad a lot of curve to your pants. You may only need it in front or back – and of course if you do 3 on one side, do three on the other…but you can have 3 in back and 2 in front or vice versa.

      Hope that makes sense!

  2. On the ones I made recently, I can pinch out about 2 inches (approximately where #4 is on your illustration) without pulling the pants down any. I’m trying to figure out if the crotch is too long or too short!

    • Donna that sounds like your crotch seam area there is too thin – what I mean is that (pretend) we cut you in half at your waist and again at your center back/center front and we took a picture of that cut out.

      This means you have too much in your inseam. That really has nothing to do with the length of your crotch. So I wouldn’t change the length of your crotch seam, but the width of it.

      Hopefully that makes sense.

  3. Thank you, Claire. Just yesterday I started to alter the crotch seam on a pair of RTW pants that were too small through that area. I was going to do as you instructed above( I had done it YEARS ago.), but lost my nerve because it seems so backwards. I’m going back to my sewing room and give it another try. Thanks again!

  4. Claire, this is making sense. And, while I know you don’t “do” much for men, what would you do for the proverbial plumber and the sagging britches? Poor husband is constantly losing his, even belted, because he has no arse! And, he likes to hitch his RTW under the belly flap. (It is much easier to fix someone else’s than mine…see how I keep avoiding the FBA? Still scared, stupid me. But, he has a much bigger issue than me with merely a poor fit. His fall off!)

    • You might think about some elastic – strong, thick elastic – probably to the side area. But just enough to “grip” and keep the pants from falling down.

      Now the truth here is that men don’t have much of a waist, that’s the natural make-up of their bod. They also have more shoulder strength than we do (our strength is in our birthin’ muscles!!! So if this doesn’t fit on the waist, then a man is not making use of the upper pelvic bone to hold his pants up. So we’re sort of entering into the hold-em-up-by-the-grab-whatever-you-can method! My DH is the same way and I put some elastic on the sides and that helps.

      • Thanks Claire. The next post helps too! You are amazing!

  5. Claire,
    Forgive my denseness! So what you’re saying is that I should shorten the inseam, right?

    • You are not dense…I know this is tough. I’m sending you an email cause I can attach pics, cause this is really hard to get your head around!

      • I sent you an email, but to share with others, thought I would try and post them here.

        The one directly above is the original version If you are pinching out fabric in your upper inseam, then you need to “thin up” your crotch seam., bring your CB & CF closer. Be careful when you do this and make sure you can sit. Pin it in and carefully sit down to see if you have the ease to sit, this is part of where your seating ease is in the pants.

        Here’s another view in the pattern piece. The one on the left is original with the inseam pinched out and the one on the right is
        the altered pattern. I’ve over exaggerated here so that you can get the idea of what you’re doing.

  6. CLAIRE,

    I resently made a pair of yoga pants for my husband.The problem is the crotch area.Its too short and tight. But the pants are good length wise. Could i just add more fabric to the waist? To make the crotch longer? Or should i just start over?

    Thanks a lot!

    • Sandra – excellent question – I answered it in my blog for this weekend (on Friday). It’s a great technique to know about and I like to post more difficult techniques and detailed ones closer to the weekend to give you all time to read through it and think about it.

      Ask away if this doesn’t answer your query!

  7. Hi, you explain yourself most clearly out of the many many blogs I have visited in my attempt to find an answer to my problem!
    I did the pinch out on the inseams, but am now encountering a problem meeting the front and back crotch seams to sew the pants back together.
    I did and the crotch is too low, same seam I took out. The back of the trousers was never the issue, just the “too much material ” in front, that the client doesn’t like.
    I am nearing my attempt at a “gusset” with only about 1.50 inches from hemline to work with, as far as extra fabric for a gusste! But then, where do I add it? Considering the “gusset” option. Help????? Sylvia

  8. Sylvia – I wouldn’t put in a gusset, cause it sounds like the “too much material” a gusset would only add it. What you may have to do is go back and forth on several issues:
    1. take in the top of the inseam from both front and back,
    2. take in the top of the inseam from the back alone (sew up front on original seam allowance line, or
    3. take in the top of the inseam from the front alone (sew up back on original seam allowance line)

    One of these will work. If this doesn’t work, then you will have to take in some on the center front above the top of the inseam – note this will have to be done so that the crotch seam is not lowered, but the height of the crotch remains the same – only the width changes.

    If you are having too much in the crotch, and have cut that fabric out, then you will need to raise the whole pant and start the fitting process on the crotch line again. Don’t worry about the hem of the pants (if they are too short – you can always add to that later).

    The most important part when adding width is NOT TO MAKE THE CROTCH SEAM LOWER – you have to keep the height the same, it’s the width you have to change. This is what makes altering this curve so difficult.

    Hope that helps.

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