Flat pattern measuring lets you sew a better-fitting garment faster. You can make significant fit improvements to a me-made garment via flat pattern measuring without touching a fiber of fabric.

Flat pattern measuring lets you sew a better-fitting garment faster. You can make significant fit improvements to a me-made garment via flat pattern measuring without touching a fiber of fabric.

Yes, flat pattern measuring takes a bit of time upfront. But, I’d rather measure sewing pattern pieces and make a few preliminary fit adjustments than stitch multiple muslins before moving on to my real-deal fabric. That’s an option for your with flat pattern measuring!

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What is Flat Pattern Measuring?

The TL;DR definition of flat pattern measuring is comparing body dimensions to the dimensions of sewing pattern pieces. Pattern pieces are flat, so… ya get the idea. Flat pattern measuring helps sewists understand the relationship between 2-D paper (and eventually fabric) and 3-D human bodies.

Why Try Flat Pattern Measuring?

I see three compelling reasons for the practice of this essential sewing activity:

1.) Before you cut fabric, you can get an idea of how a pattern will work for your body.

If flat pattern measurements are significantly larger than your body measurements, the pattern has a lot of ease or you need to size down. If the flat pattern measurements are smaller or close to your body measurements, the pattern has little or negative ease (and if it’s a pattern for wovens, you might want to think about sizing up).

2.) Flat pattern measuring helps you sew a garment faster.

That’s because you’ll likely have fewer fitting adjustments and fewer (or zero!) muslins to sew. You can make adjustments to paper pattern pieces BEFORE you cut them from fabric. Don’t waste fabric!

3.) You can work those verticals.

Most patterns do a great job with horizontal/circumference measurements and a less-than-great job with vertical measurements. I am long waisted and have long arms, so it’s wise for me to measure back length and arm length on flat pattern pieces before I get underway. That way, I can add length preemptively. S-M-A-R-T.

Flat Pattern Measuring Step by Step

Follow these steps to measure sewing pattern pieces.

1.) Measure your body.

Whip out that measuring tape and check your sewing pattern for which dimensions are germane to the project. For example, if you’re sewing a shirt, you’ll need to know:

  • Full bust circumference: Around fullest part of bust, parallel to the floor.
  • Waist circumference: Around narrowest part of torso, parallel to the floor.
  • Backs lengths (to understand where the shirt will fall):
    • Back of neck to waist
    • Back of neck to high hip
    • Back of neck to full hip
  • Back width: back of shoulder blades, from line where your arm meets your torso (aka, (likely) the widest part of your back).
  • Shoulders: from where neck joins shoulder to end of shoulder; doesn’t hurt to measure both shoulders, as your body may be asymmetrical.
  • Arm/sleeve length: From end of shoulder to wrist (or where you want the sleeve to end).
  • Bicep circumference: Around the girthiest part of your upper arm (aka, the biggest part of your “ticket to the gun show”).

RELATED: How to Make a Full Bust Adjustment on T-Shirts (No Darts)

When flat pattern measuring for a shirt, you must take corresponding body measurements.

If you’re sewing pants, you’ll need to know:

  • Full hip circumference: Around fullest part of lower body, parallel to floor.
  • High hip (top of pelvis-ish) circumference: Parallel to floor.
  • Waist location (where you’d like the pants to sit; sometimes this isn’t the narrowest part of your body) AND waist location circumference: Parallel to floor.
  • Crotch length: between your legs, from front waist to back waist.
  • Crotch depth: when you sit, measure from waist location to the seat where your booty (hip) hits the chair.
  • Leg inseam: crotch to ankle inside leg.
  • Outer seam: waist to ankle outside leg.
  • Calf and thigh circumference: if the pattern is particularly fitted and you feel like your circumferences are outside the sizing bell curve (e.g., wide calves).

Sewing Pants That Fit: A 3-Part Series
Pattern Fitting Tips for Woven Jogger Pants (Pivot-and-Slide Method)

When flat pattern measuring for pants, take corresponding body measurements.

In general, the more measurements you take, the more points of data you have for comparison against the sewing pattern, which gives you more opportunities for adjustment. Measure as much or as little as you want.

ALSO: Keep track of vertical distances from body “landmarks.” For example, take note of the the distance from your crotch to your thigh circumference location. That way, when you’re measuring thigh circumference on the pattern piece, you can measure down from the crotch point. It’s not perfect because there’s ease in the crotch so technically it’s lower than your body crotch, but it’ll give you a decent spot for a horizontal measurement.

Continuing on this theme, use the end of your shoulder as a landmark for bicep circumference and your waist as reference for high hip circumference. Think in terms of an X-Y axis: You need to move this far left or right and this far up or down. Have both X and Y “coordinates.”

2.) Choose a size.

Check out the sewing pattern’s size chart and choose your choice based on your measurements. Your measurements may put you between sizes. Go with the smaller size, because it’s easier to size up than to size down. You’ll use this size for flat pattern measuring.

3.) Mark seam allowances on pattern pieces.

Check directions (or pattern pieces) for seam allowances, and mark seam allowances at critical measurement points β€” bust, hips, waist, etc. β€” on critical pattern pieces. (In the pattern piece graphics below, the seam allowance is pink.) You don’t have to mark the whole seam allowance perimeter, and you don’t have to mark every pattern piece, either.

And instead of marking seam allowances, you *could* measure pattern pieces and subtract the seam allowance. I think, however, it’s REALLY easy to forget to subtract. My two cents.

4.) Measure pattern pieces from seam allowance to seam allowance.

As you’re measuring, be thoughtful about WHAT you’re measuring and what it means; think about how many pattern pieces work together for each body dimension.

For example, as you measure the bust of a standard front bodice pattern piece (as illustrated), this number is ONE HALF of the total FRONT bust circumference. The back bodice pattern piece contains ONE HALF of the total BACK bust circumference:

(Front Bust x 2) + (Back Bust x 2) = Total Bust Circumference

Don’t forget to write down your findings (also easy to forget). These findings are your finished garment measurements. (You can check against the pattern envelope if finished garment measurements are included.)

P.S. If the pattern piece is cut on the fold, measure from the seam allowance to the fold; there’s no seam allowance with a fold.

P.P.S. Don’t forget about cuffs, waistbands, collars, etc., when measuring pattern pieces. They contribute to total lengths! (I only showed the main pattern pieces you’d be measuring.)

Here's how to make measurements on shirt pattern pieces.
Here's how to make measurements on pants pattern pieces.

5.) Determine ease.

There’s wearing ease and design ease. You need wearing ease to fit into and move around in an article of clothing in comfort. Wearing ease is functional. To compare, design ease is ease ON TOP OF wearing ease. And then there’s negative ease, which is when finished garment measurements are SMALLER than body measurements. You need negative ease in some knit clothes (e.g., leggings, swimwear).

Here are some recommendations for wearing ease from Threads magazine:

MeasurementWearing Ease
Bust Circumference2-4 inches; 3-5 inches for outerwear
Back Width3/4 inches-1 inch; 1-2 for outerwear
Bicep Circumference1 1/2-2 1/2 inches; 3-6 inches for outerwear
Waist Circumference1 inch
Hip Circumference2-4 inches
Crotch Length1-2 inches
Crotch Depth 1/2 inches-1 inch

Please note that plus-sized bodies with greater volume may need more ease. Make a muslin to discover your ideal ease. In my experience, when I’ve sewn a Big 4 (non-indie) pattern and it wasn’t working, it was because of the ease.

To discover design ease (which is the ease you can experiment with and still have a garment in which you can move), follow this formula:

(Finished Garment Measurement – Size Measurement) – Wearing Ease = Design Ease

For example, let’s say I measure pattern pieces for a button-up shirt and find its finished garment waist circumference for a size 6 is 28 inches. Let’s say the size 6 waist measurement (per the pattern size chart) is 26 inches.

(28 inches – 26 inches) – 1 inch = 1 inch of Design Ease

As long as the pattern gives you the body dimension in a size chart, you can find out design ease for that body zone.

6.) Make adjustments.

Adjustments are based on comparing your body measurements to size chart measurements to flat pattern piece measurements and ease. Here’s an example that helps to illuminate a possible adjustment.

Let’s again say I’m sewing a button-up dress shirt. Here are some numbers to work with:

DimensionMy Body (in.)Pattern (in.) – Size 6Difference (in.)

These data tell me that I need to add 2 inches TOTAL to the waist and 2 inches TOTAL to the to hips. To make these adjustments I can:

1.) Trace off or cut out pattern pieces that fall between two sizes. With this (fictional) pattern, I’m a size 6 in the bust but a size 8 in the waist and hips. It should be easy to gently curve between 6 and 8.

2.) Use the Nancy Zieman pivot-and-slide method, as described in this 8-minute video. This is EASILY my favorite way to make pattern adjustments. Hashtag “Sewing with Nancy” forever. ALSO: This book, “Pattern Fitting with Confidence,” is the print version of this technique. I own this, and it’s excellent as well.

3.) Use another adjustment method. Hey, there’s no shortage of adjustment methods. (See list of books below, the internet, Pinterest, and/or YouTube. Use techniques that make the most sense to YOU!)

A Word About Ease and Adjustments

You may question the value of finding ease when, for some body measurements, you make the adjustment based on the difference between your body and the pattern size chart.

Pattern designers have an opinion about design ease as they create a garment. Calculating design ease lets you know the designer’s vision for ease relative to the body. That way, if you please, your adjustments can preserve this relativity.

Or, if you please, you can look at the total ease, decide it will accommodate your body just fine, and skip the adjustments. This also is totally legit. For example, Cass, Sie Macht’s free T-shirt PDF pattern, has generous design ease in the bust, waist, and hips BY DESIGN. My M.O. was to make fit adjustments extremely optional!

Sewists are in charge of the fit of the clothes they make for their bodies. Yes, there are “standards” of fit, but, at the end of the day, fit is subjective. If it makes you feel good, your fit is as it should be.

I hope you see the value of measuring flat pattern pieces and feel comfortable whipping out that measuring tape! IMO it doesn’t add much time to your overall project experience, and I, for one, would rather make some flat pattern measurements (and adjustments) than multiple test garments!

Over to you: What’s your method for flat pattern measuring? Do you take this critical step? If not, why not? Pleas sound off in comments! Thanks for reading (and for sharing this post with fellow sewists, especially via Pinterest).

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