This is the most frequent question, and the one sellers answer most poorly. "Take the thickest one, it's more comfortable": this is false, and it explains why so many mats end up rolled up in a closet.
Thickness is not a matter of comfort. It's a trade-off between stability and cushioning. The thicker the mat, the more it protects your joints — but the more it makes you lose the ground contact you need for balance.
3 mm: stability first and foremost
This is the thickness for dynamic yoga, vinyasa, and Ashtanga practitioners. You feel the ground under your feet, your support is firm, and balance poses — tree pose, warrior III, forearm stand — become much more accessible.
The downside: prolonged floor work becomes uncomfortable. A two-minute plank on 3 mm, elbows on the ground, takes its toll.
Choose 3 mm if your practice is standing, dynamic, focused on sequences and balance. It's also the best thickness for transport: a 3 mm mat rolls up tightly and slips into a sports bag without overflowing.
4 mm: the compromise that suits most people
If you're unsure, choose this one. The 4 mm absorbs enough so that your knees and elbows don't suffer, without destabilizing you in standing poses.
This is the thickness to favor if your session mixes different types of exercises: a bit of yoga, core work, a few push-ups, stretching. In other words, the practice of most people who train at home.
6 mm: joint comfort
Here, we're no longer talking about yoga but about protection. The 6 mm is made for long floor sessions, Pilates, stretching, rehabilitation — and for anyone with sensitive knees or a hard floor, tile or hardwood on a concrete slab.
It's also the obvious choice if you use an ab wheel: the movement puts direct pressure on the knees, and 3 mm is not enough.
Its drawback: in balance poses, the foam sinks under pressure and you lose your stability.
The criterion everyone forgets
Before thickness, look at the material. A TPE mat, without PVC or phthalates, grips better when your hands sweat, doesn't emit a chemical odor, and ages without crumbling. A cheap PVC mat becomes slippery from the first intense session — and a slippery mat is a dangerous mat.
Also look at the surface. A non-slip double-sided mat stays on the floor as much as it stays under your hands. This prevents it from rippling with every change of posture.
In summary
- Dynamic yoga, balance, frequent transport → 3 mm
- Mixed practice, you're unsure → 4 mm
- Pilates, stretching, hard floor, sensitive knees → 6 mm
The FORJ fitness mat is available in all three thicknesses, in double-sided non-slip TPE, with a carrying strap included. Find it in our Yoga, Pilates & Mobility collection.