The sizing of the oval bangle depends on how “oval” it is: some bangle is like 58x50, some 60x50, and lately I saw a lot of them come in 56x52, or 55x51. So you see the bigger the difference of the 2 diameters, the more oval it looks and also it should fit differently if two oval bangles have the same longer diameter but different shorter diameters. The smallest round bangle I can put on without chopping my thumb off (on my left hand) is 53mm. I bought two oval bangles-one 55x51 and the other 56x52. So basically most people hear something like adding the two diameters and divide by 2 to get the equivalent size. So most will be certain the 55-51 oval will fit similar to my 53 round, but I guarantee you it was not the case with me-I had much more difficulty putting that one on-it came on and left blood spots bursted from tiny veins around my knuckle. On the other hand, the 56/52 oval came on much like my typical 53 round. So if you can fit the 55 round shape, you may want to look for ovals of 58x54(most likely comfortable),and 60x52 (if you don’t have meaty hands). Avoid too big oval bangles if you don’t have meaty hand/wrist-i.e you just may be taller with larger bones/palm width, though. I bought a 60X50 and while the shorter diameter was 3 mm less than my 53 round, it looked ridiculous on my wrist because the shorter side flipped around so it totally defeated the purpose of wearing an oval bangle. So a 60x52 may do the same to you. I suggest you buy something like 58x54 and see if you need to go up or down.
Have a good weekend Jadies.