Below are the details about the average cost of the diamond ring. The national average cost for a diamond ring is $5,855. This means 50% of people purchase diamond rings below this range, and the other 50% people go above this range. However, you can choose this as a starting range to purchase stunning diamond rings.     How to Determine the Price of a Diamond Ring The price of a diamond ring is determined by the value of diamonds used in the ring and the type of settings used. However, most diamond merchants display their diamond rings in the stores without a center diamond. For instance, a three diamond platinum ring will cost only $3000. This will not include the center diamond. Therefore, the actual price of your ring will be way different from the displayed price. Some jewelers will display the overall price of the ring including the center stone. It is better to choose this type of rings for research, as they will give you an idea about the price of diamonds used and the settings on the ring.