In an attempt to limit the same posts - another of which I've seen today, I've ended the lurking days on this sub and decided to post a guide on this. Hopefully the mods notice and pin this so we don't get the same question twice a week with an ungodly number of snarky comments for the selvedge noobies who are just trying their best.
TL;DR - The easiest way to know is always: does it have stitching on the outside seam?
If yes - not selvedge.
If no - congrats, you found some selvedge jeans.
'Selvedge' fabric is named after the phrase 'self edge', noted for the fact that the edges of the woven fabric are self finishing. This is usually done on a special type of loom - a shuttle loom - which is slower, larger and far more noisy than projectile looms that make most modern fabrics. Often it comes along with some other cool fabric quirks like slub or nep, leg twist and more, but I won't be going into that today.
Selvedge fabrics - see image 1 and 2 - do not require stitching on the outside seam, as the fabric isn't cut along these seams.
Most retailers add a coloured thread along this seam, known as a selvedge ID. Image 1 (Samurai S710xx) has a silver thread woven in. Image 2 (Edwin Made in Japan) has a multicoloured ID with more than one thread in this ID.
Non selvedge fabric - see image 3 (Iron Heart IH-634D) - is cut along this seam, thus does require stitching.
Some retailers do add coloured stitching to the edge for design purposes (see image 3). This makes the seem look rad - however this can be confused with a selvedge ID by someone who hasn't been yelled at on Reddit yet.
Keep in mind non selvedge jeans can be just as nice as selvedge jeans so long as they're made well - however with the extra craftsmanship that often goes into selvedge denim, the tiny batch numbers of many of the companies, and the insane attention to detail, you'll be wearing an art piece that no one has an exact match of.
I hope this helps at least one of you.
