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How to use Sewing Blocks


What are “blocks”, where do I get them, and how do I use them?

Previously I blogged about  how a  basic SLOPER is used to make multiple BLOCKS, which are used to create endless PATTERNS.

When you hear the word “block” in regard to sewing, think of “building blocks”.  They are to fashion patterns what base recipes are to the chef: tried-and-true foundations to build from. Blocks are sometimes called “working patterns” because, unlike slopers or even “fitting shells”, blocks include both “wearing ease”  but also “design ease”:

Sloper + seam allowance( for sewing) + wearing ease (for fit/comfort) + design ease (for style/silhouette)= Block. 

Slopers are useful, but blocks are  a step closer to getting the silhouette and fashion that you want. When sewing apparel for yourself, having a  tested block  lets you avoid re-solving fit issues each time you create a new fashion pattern, or buy a new commercial pattern.  It also helps you determine which designers use blocks that best flatter your own body type (apple, pear, etc), and have the wearing ease you find most comfortable. while you can easily see the designer’s style aesthetic from their photos and sketches,  you can more easily determine their fit through blocks.  Many  designers work with a sloper that mimics their own body type, and blocks that flatter that shape.  For example  Judy Hale at “Patterns for Pirates” explains that her patterns are designed for the  hourglass figure:


(Illustration courtesy of Judy Hale)

Just as finding the RTW brand whose blocks  fit and flatter you lets you shop online with fewer returns (and shop in stores with less trying on.), it’s the same with patterns: if you know the designer and the blocks that work for your body, then you can jump into sewing faster without fewer alterations and greater chances of fitting success.


Where do I get my own personal blocks?

Depending on how much time you have to invest, and how comfortable you are with drafting, you can make your own blocks from a personal sloper (direct method), OR you can curate a collection of blocks from commercial patterns that you  tweak to fit your particular figure (indirect method).

DIRECT METHOD: for people with plenty of time, who love drafting, begin with a sloper:

  1. Learn to make a sloper from a sloper-drafting book (recommended books include “How to Draft Basic Patterns”or “Patternmaking for Fashion Design”)
  2. Take an online
  3. Study from a blog:
  4. Use a sloper service, where you send in your measurements and a personal sloper is created for you:  Kosher PatternsPatternmakerPattern Stringcodes
  5. Buy a fitting shell pattern (fitting shell = sloper plus minimal wearing ease but NOT design ease) from McCalls, Butterick, or Vogue (illustrations left to right):

Mccalls shellButerick shellVogueShell

McCalls  M2718  :

Butterick B5627:

Vogue V1004:

(McCalls shell is by Palmer/Pletsch.  The Butterick/Vogue shells are the same pattern)


From there, you test and tweak your patterns until you are pleased with the fit and the silhouette. You can learn from a good apparel-design book about how to manipulate garment shapes through the “pivot-and-slide” and “slash-and-spread” methods:


Recommended design textbooks are (from the bottom up):

“Designing Apparel Through the Flat Pattern”

“Basic Pattern Skills for Fashion Design”

Creative Pattern Skills for Fashion- Design

Patternmaking for Fashion Design” (for both sloper drafting AND apparel design)

..and finally on top, a very affordable paperback reprint of ““Make Your Own Dress Patterns” by the incomparable  Adele P. Margolis.


INDIRECT METHOD: for those with less time, who are not crazy about drafting, or just love to sew and  want to get going:

Leave it to the experts.  Buy basic commercial patterns in the silhouettes you love, test to fit.  Sounds simple, right?  Sewing patterns already have both the fit ease  and the design ease built in, so voila! But truthfully this still takes time, because there are endless patterns available, and they change with the seasons and fashion trends .  Try joining Pattern Review boards online, ask sewing friends and family for their favorite pattern numbers, study the pattern catalogs in the shops by looking at the photos and seeing if you like the way each garment fits. Curating a collections of blocks takes time, but (possibly) less time than starting from scratch.


How do I use my blocks?

  1. As basic sewing patterns: you can use  blocks directly as patterns, for basic styles. Take your basic block for a classic short-sleeve crew-neck tee-shirt. Use the block as is… modify it for scoop-neck, vee-neck, or boat-neck….adjust the sleeve to cap-sleeve, 3/4 sleeve,or long-sleeve. One block, many looks.
  1. For development into fresh patterns:   Take that same tee-shirt block that you already know fits you, add length and design ease to create a swim-cover, a night-shirt, or a beach maxi. For example, look at the variety of dresses that are possible with this one dress block from Kosher Patterns:


My Sloper Dress Styles 1.71

(Illustration courtesy of Mrs. Chesler at Kosher Patterns)


3. To check against commercial patterns for correct fit: let’s say you’re a new sewist, and you’ve successfully used “straight line stitching” patterns for twirl skirts and simple pillowcases dresses.  Now you’d like to graduate to more fitted SHAPED patterns which  means patterns pieces that are CURVED, but you’re not comfortable drafting sleeve-caps, armscyes, and pants rises. You can hunt down a great-fitting pattern, and use that as your block.

Let’s see how that works, using 3 FREE pdf patterns, since that way I can show the entire pattern pieces. My favorite-fitting kids’ pant blocks were designed by the ultra-talented Kerstin Martennson for her company Kwik Sew, which are sometimes available on Ebay. You can download a very similarly shaped block  for free from Oliver & S:  the “Sunny Day Shorts“.    Then  place this basic block on top of any new-to-you pants pattern and instantly see if you can use the  pattern as-is, make adjustments, or scrap the new pattern altogether and move on.

NOTE: No one pattern fits everybody!  Even though kids have fewer shape “issues” than adults, they still have variety, and this block won’t be the best fit on all kids…maybe not your kid!  I’m using it an example because I personally have had a lot of success with it, for my clients.  As always, I suggest making a muslin before cutting into your “real” fabric.

This is Sunny Day: the back rise (left side in photo) has an ideal angle and French-curved shape that fits over a child’s bum to avoid “wedgies”, and enough rise height to avoid “plumber’s crack”. The front rise (right side in photo) has a shorter rise height to avoid bubbling or “wadding” when sitting, and a nicely extended  crotch hook to avoid “crotch bite”. Apologies for the yucky terminology. I need to find some nicer ways to express these fit issues……suggestions are most welcome!

IMG_8343 copy


Let’s say I’m interested in trying  the  “Taylor’s Pajama Pant” available for free from CKC through Note that the back and front rises are the same height, since the pattern is cut on the fold, so already I know there will be “bubbling” in the front rise. The back and front rises are also the same shape (bums and bellies do not have the same shape!) but we’ll see in a minute how  the rise angles and crotch shapes compare to the pant block that I trust:

IMG_8354 copy


I place Sunny Day on top of Taylor’s (please disregard the differences in overall height, as Sunny Day gets a separate waistband): the thigh measures are identical (these are children’s  size 4)….the waist measure of Taylor’s is bigger, which is fine (I wouldn’t want it to be any smaller than my trusted block) but keep in mind: Fit is not defined as having enough fabric to cover body parts.  Especially when fitting curved body parts as you do in pants, it’s not about the measurements, it’s all about the SHAPE.   Here the shape and angle of the rises are very different between the two designs (kind of looks like Taylor‘s has two front rises?:


First the BACK rise, Taylors (underneath) has hardly any scoop to accommodate the shape of a child’s bum:



For the FRONT rise, Taylor’s (underneath has no “hook” to go under the crotch:


(For a fuller explanation of the pitfalls of pants with not enough curve in the back and front rises, and not enough hook going under the crotch, read Kathleen Fasanella’s blogpost, which also explains how this happens in mass production when factories  skimp on yardage yield by slightly altering the SHAPE of pattern pieces, all the while maintaining the specification MEASUREMENTS.  Shape is subjective, measurements are objective. Retailers will reject an apparel shipment if the merchandise is off-specification measurements, but its much more difficult to prove the shape has been revised. Warning: if you are at all interested in correctly fitting patterns, pour yourself a cup of tea first, because her blog is addictive.)



Next up from free from Dana Made It“Kids Pants” (but only in size 2/3): these appear better than the “cut-on-a-fold” pants, as there is a clearly different front and back:


As they are a size smaller than the Sunny Day, it’s not possible to compare the width (waist measure and hip measure) since these are two different sizes, but let’s look at the angle and shape of the rises: much better than before..but not great yet:


(Okay now I have to flip the pattern pieces over so you can compare more clearly)

First the BACK rise, Kids Pants (underneath, pink) has hardly any scoop to accommodate the shape of a child’s bum:



For the FRONT rise, Kids Pant (underneath, pink has no “hook” to go under the crotch:



Now let’s compare the rises of all three patterns in 3D by pinning the pattern inseams as they would be stitched.  First up is Sunny Day; imagine a child’s body inside, bum to the left and belly to the right….it looks like a comfortable shape:

IMG_8348 copy


And here’s Taylor’s in 3D: the back rise on the left is going to give a “wedgie”, and the front rise on the right is going to have “crotch bite”:

IMG_8349 copy


And here is Kids Pants: rise heights are better, but crotch shape has the same issues as Taylor’s:


The only way to make Taylor’s and Kids Pants wearable  (without extensive adjustment) is to cut your pattern and fabric several sizes too large for your child.  Which means you are not “fitting”….you are simply covering up the body.


Now let’s try a completely different pattern, this is Aivilo  Charlotte’s High Tide” shorts pattern, (not free, so I’m not showing the whole pattern pieces) which has the same thigh and waist measurements as “Sunny Day”.  First let’s look at the BACK rise (High Tide on bottom, Sunny Day on top) : pretty nice shape! I would add a bit more back scoop and “hook” extension, based on my personal experience with the fit of “Sunny Day”. If  I find there’s excess fabric when fitting the muslin, I can pin it: it’s easier to take-in than to let-out:



This is the FRONT rise (High Tide on bottom, Sunny Day on top): the shapes are slightly different but the “hook” extension going under the crotch measures about the same, so I can choose to transfer the exact fit of Sunny Day, or else test the High Tide as-is and see how it fits.



And here’s High Tide in 3D:  the crotch has a very nice smooth shape, I can envision a cute little body fitting in there. Personally I’m going to want that bit of extra scoop in back from Sunny Day (these would have fit my very slim older sister as a kid, but unfortunately not me!). Overall I’d say this will probably be a nicely fitting pattern as-is, and I would be fine with going straight into muslin-making:



So that’s how you can use your tried-and-true blocks, to check on the fit of  new-to-you patterns and designers, and make any “tweaks” BEFORE cutting out your fitting muslin, saving you both time and money.  And frustration.

What are YOUR favorite blocks?

(Note: added March 5, 2016: I just saw a Wrangler’s advertisement on  YouTube explaining that their jeans are more comfortable because they have the U-fit as opposed to the V-fit …..yes!  You are want the U-fit.  That’s what I’m going to call it now.  Unless Wranglers copyrighted the term.  Probably have already. Darn it.)






  • Brooke

    This is super helpful as I am thinking about sewing up shorts for my kids soon. I have a couple that are skinny and the KID shorts fit well, but two that are average and there isn’t enough ease for in the KID shorts. Now I know why!

  • Chris

    Those 3D pictures are SO helpful! I’m relatively new to sewing, and I never thought of that before!

  • Bunny

    This is a wonderful post, Janet and so informative. You have helped many here. I’ve made my own pants sloper but also have used patterns for blocks. A good start is a princess seamed shirt and a darted shirt. That covers a lot of ground. Thanks, again.

  • [email protected]

    The biggest challenge for most people when beginning sewing is figuring out how those 2D patterns are going to look in 3D, so don’t be afraid to play around with your pattern pieces!

  • Sarah S

    Very helpful! My daughter needs a whole new pile of shorts for summer and I’ve been trying out several different patterns. I could see the crotch curves looked different, but this clarifies some of the fit issues! Now to try my hand at modifying them…

  • Abigail Doyle

    I love this post!!! Just shared it with my patternmaking teacher too, so she can refer her students here to get a better understanding of what she’s been telling them. The funny thing is I had bought the MADE shorts for my son and couldn’t understand why they weren’t fitting properly until I read this. DUHHHH moment. I’m so ashamed that I hadn’t even thought of checking the pattern rise on a kids pattern. Very guilty of thinking all kids are the same, even though I know full well that each body is so different. I plan on drafting a pants block for him during the Easter break so I can get cracking on some much needed bottoms for his wardrobe. Thanks again for this post!

  • [email protected]

    Thank you!! Where are you studying patternmaking? I LOVED my patternmaking classes…actually more than my design classes! Some people like the sketching better, I liked the technical part. Have fun sewing for your little guy…take lots of pictures, they grow up way too fast!

  • JustGail

    Thank you for so clearly showing the fit issues for pants patterns, and especially for the 3D models. I’ve seen a tip about making a personal curve using either a flex ruler or a roll made of crunched up foil, now I really see how that would help. Does this better fitting U shape also help with range of motion? I always thought the Wranglers commercial was talking about being able to ride more comfortably, not that they wouldn’t cut in while not riding.

  • [email protected]

    A flex-ruler is great for getting your personal curve shape. I believe the correct rise shape is more for comfortable fit; I don’t know what the effect is on range of motion…I should look into this!

  • Lola B.

    Thank goodness for people like you and Kathleen Fasanella! I spent too many years angry at my body until the day I stumbled across a blog post that explained the reasons why I could never find comfortable shorts. I’m excited to see the changes that your blog will inevitably cause; there really is no excuse for the overcharging/under delivering that some indie designers have turned into a business model. I shudder to think at how much money I’ve wasted in ink, paper, tape, fabric, and time *sigh* Anywho, thanks again and please let me know if there’s any way to support your site 🙂

  • [email protected]

    Don’t you just love Kathleen?? Yup, I always struggling with my own pear-shape, high-hip, short-waisted body that doesn’t take kindly to pants and shorts. Even photos of me as a kid, so obvious that my sister and I should not have been put in matching outfits….she can wear straight off the rack. Me? Not so much. But don’t blame yourself for money spent on patterns…think of it as money invested in learning. I learn with every garment I make and I’ll bet you do too! Thanks for the kind words Lola!

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  • [email protected]

    Hi Hannah, this blog is on the WordPress platform, hosted by BlueHost. I’m not thrilled with either one, honestly. WordPress is too complicated for my needs, and Bluehost has such strict limits on bandwidth that my site gets interrupted constantly. I don’t have any recommendations though….I need to do some research!

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