I recently acquired the Cartier Classic Trinity ring, and it’s a gorgeous addition to my Cartier Trinity collection. (I’ve included pictures below.) My first experience with the Trinity ring was trying on the extra small model at the boutique in Chicago. At the time, I didn’t feel like the extra small model was substantial enough to add to my collection. The narrow bands almost didn’t feel like metal. However, this experience taught me an important lesson about sizing for the Cartier Trinity rings. I learned that I wear a size 48. For reference, my ring size at the time was a size 5 in narrow and wide bands. (More sizing tips are included below.)

Flash forward a few years and I have now obtained the Cartier Trinity necklace and bracelet. I decided that I wanted to add the small model or classic model to my collection, and I was fortunate enough to be on vacation in a location with a Cartier boutique within walking distance. I tried on the small and classic models, and decided on the classic. It’s a beautiful ring, and it matches well with my Trinity bracelet. I only have two comments.

First, you have to align the bands in a certain way in order to get the ring on your finger properly. You will know it’s on properly if it rolls smoothly onto your finger. If it feels snug or stuck, remove it, realign the bands, and try again until the ring rolls on smoothly. This can sometimes take two or three attempts.

Second, the ring tends to hold a bit of water after hand washing. You will need to move the bands around on your finger while drying your hands in order to get the water out. The Cartier Trinity ring is not nearly as bad as byzantine rings, which are the worst at holding water, and basically unwearable in my opinion. But you do have to take a bit more care when you’re drying your hands with the Trinity ring to ensure that you get all the water out from between the bands. You may want to purchase a low-cost rolling ring to wear for a few weeks to be certain that it’s a style you will enjoy wearing over the long term.

Cartier Trinity Ring Sizing Tips based on my experience:

For reference, my ring size is now a 4.75 in narrow bands and a size 5 in wider bands. The Cartier Trinity small and classic models are both wider bands, so it’s safe to assume I would be a size 5 for reference. The size 48 in the classic model fit perfectly. I found the 48 in the small model to be too snug. Size 49 in both models was too large.

(Note: The primary reason I chose the classic model over the small model was due to sizing. The small model is lovely and might have matched a little better with my Trinity bracelet, but size 48 was too tight and size 49 was too loose. The classic model fit perfectly.)

GENERAL SIZING: I wear ring size US 5 in thicker bands. Cartier indicates online that ring size US 5 converts to size 49.5, however size 49 or larger would have been too big for me in the small and classic models. Size 48 in the classic model was a perfect fit, which converts to a size 4.5 per Cartier online. I would have needed a 48.5 in the small model, which is not an option.

CLASSIC TRINITY RING SIZING: Cartier recommends that you select a size two sizes smaller than indicated in the Cartier Ring Size Chart. For instance, should your usual size be 50, select a size 48 for the Classic or Large Model Trinity rings. My usual size per the Cartier Ring Size Chart would be a 49.5, which is not an option. Assuming I use the next size up (size 50), this would have worked for me in the classic model. A size 48 was the perfect size (i.e., two sizes smaller than 50).

For Cartier Trinity, I believe you need to try the ring on in person to be certain of the size. As I mentioned above, the extra small model and the classic model in size 48 fit me perfectly, but the size 48 in the small model was too snug.

If you cannot try the Trinity ring on in person, I recommend using one or more ring sizers, such as the ones pictured immediately below to try to gauge your size as a starting point. I strongly recommend calling your nearest Cartier boutique for assistance or visiting in person if possible.

GGZ Cartier Classic Trinity Ring Sizers.jpg

Cartier Trinity Ring Classic Model. I’ve included pictures that show the different ways you can set the ring on your finger to highlight either the white, yellow, or rose gold. The Cartier name is etched on the rose gold band.