If you are correct in measuring your wrist bone and say it's 13.5 cm, then I would say size 15 is perfect for you. I think adding 1.5 cm to your wrist bone gives a perfect comfort fit if you don't want the tight fit.
My wrist bone is 14-14.25; therefore, I went with a size 16. You can print out the Cartier wrist sizer and measure it to your wrist bone. That is how I was able to figure out the perfect fit for myself even though I fit both sizes.
This method of adding 1.5 cm to your wrist bone allows the bracelet to fall about 1/3 down the length of your arm which I think allows a very comfortable fit. Another method I read is making a fist with your other hand and placing your knuckles starting at the wrist bone, and if your fist fits that area from wrist bone to bracelet, it's PERFECT!
your wrist bone size is perfect for 16! It’s the 2cm I dreamed of lol
I definitely should get size 15 according to cartiers official website lol. But I think they don’t really count for the swelling or stacking ( they def don’t recommend to stack lol)
I have very tiny bones. But my arm is just a little bit meaty.So I think my arms get thicker a bit quicker than normal people, if you know what I mean. Maybe that’s why it can only go up to less than 1/3