What size ring should I get for an engagement?

The best size is the exact one that fits comfortably. If you are choosing together, go to a jeweller and get measured properly. If you are planning a surprise, try to borrow a ring the person wears on their ring finger, or ask their mum, sister or close friend to find out discreetly. Many people wear a ring on their right hand that is a similar size, so you could borrow that. If you cannot get any measurement, a common starting point for women is size L or M, and for men size T or U. But these are only guesses, and fingers vary a lot. The safest option is to buy from a jeweller that offers free resizing within the first few months. Most rings can be resized by one or two sizes, but some designs, like rings with stones all the way around, are harder to resize. Always ask about the resize policy before you buy, and keep the receipt. If the ring is too big, you should not wear it until it is resized, because it could slip off and get lost. If it is too small, it can be uncomfortable and hard to remove.