How to measure the inseam of jeans & pants guide
By Maurice Malone Published March 20, 2020, Updated with Jack Matthews July 4, 2021
One of the most common questions asked is how to measure the inseam on jeans and pants. When it comes to alteration services, tailors, and brands, not everyone measures the inseam in the same manner, especially when measuring jeans.
We start by admitting there is no single true way to measure the inseam. The truth is, it all depends on the construction of the pants or jeans you plan to measure. First, we will be explaining the most common sort of seam line construction found at the front and back rise of jeans: Flat-felled.
Does measuring start from the seam line, or between the two stitch lines?
The point of confusion begins with where to start the measurement in the crotch. Is it from the seam line (as we recommended in the past), or do we start from the center of the two stitch lines?
After some internal debate and experiments, we concluded if the jeans or pants are constructed with flat-felled seams in the crotch (front & rear rise seams), the correct center of the inseam would be at the center of the double-needle stitch lines. The starting point would be as shown in the photo above.
In the past, like many, we figured the dividing point of two sides of pattern panels would be the seam line. However, that is not the case with flat-felled seam constructions. It is actually the center of the seam allowance.
The seam line would be the center point in the crotch only if the jeans or pants are constructed with overlock seams in both the front and rear rises. This is rarely the case but can be more likely in pants and trousers.
Here's where things get tricky. Some brands use an overlock construction at the front rise, with flat-felled rear seams. For aesthetic purposes, the seam lines are even in the crotch, although the exact inseam length of the rear and front sides is slightly different by a very small amount. In this case, do you measure the seam line, or between the stitch lines on the rear legs?
The next step is to lay your pants flat over a surface large enough to fit the entire pair. You would want to exclude any creases as they will interfere with your inseam measurement. Using a flexible measuring tape, run your fingers over the tape, along the inseam of the jeans, smoothing out any bumps or creases, while working your way down to the leg opening (hem). This step is the same for both pants and jeans. Use the image above as an example guide.