Why towels have those strange lines — and what they actually do

Those decorative-looking stripes on your bath towel aren’t just for show — they help prevent fraying, improve absorbency, and guide how you fold it.

A simple question recently stirred a wave of curiosity online: what’s the deal with the line running across many bath towels? An X (formerly Twitter) user asked, and thousands responded with humor, theories, and genuine confusion.

While some joked about “face-to-butt boundaries” or “racing stripes” for faster drying, others were eager to find out the real story.

So, what is that line on the towel?

The answer is surprisingly practical. That line is called a dobby border, and it plays a key role in how towels function.

According to textile makers like Towel Hub, the dobby border helps strengthen the structure of a towel. It prevents the fabric from becoming too bulky at the edges and keeps it from fraying over time — especially after repeated washes.

More than just a pretty stripe

Beyond durability, the dobby border also helps balance the towel’s absorbency and softness. It ensures the towel remains effective without feeling overly heavy.

There’s also an aesthetic side to it. The clean line adds a polished finish and offers a visual cue that can help when folding or hanging the towel neatly.

It’s easy to overlook small design elements like this, but they’re often what make everyday items work better. So next time you’re drying off, you’ll know — that stripe isn’t just there for style. It’s a smart detail that makes your towel stronger and more useful.

And if you’ve always wondered about it, now you’ve got a surprisingly useful piece of knowledge to share.