A promise ring most commonly goes on the ring finger of the left hand. This tradition symbolizes a direct path to the heart and is the same finger that an engagement or wedding ring is later worn on. It's a sign of commitment and a potential step toward engagement or marriage. Some people wear their promise ring on the right hand ring finger, especially after engagement or to signify a different stage of commitment. Others may choose different fingers based on comfort or personal style, including the middle finger, pinky, or even wearing the ring on a necklace. Ultimately, there is no strict rule, and wearing a promise ring is very much a personal choice reflecting what the ring means to the wearer. Summary:

• Most common: left hand, ring finger (traditional, symbolic of commitment leading to engagement)
• Alternative: right hand ring finger (post-engagement or alternative commitment)
• Other fingers or hands: based on personal preference and comfort

This tradition applies across genders and relationship types. Therefore, the best answer is that a promise ring typically goes on the ring finger of the left hand, but it may be worn on other fingers or the right hand depending on individual choice and meaning.