When planning a surprise proposal, the biggest concern is often the "ring size." But don't worry if you don't know the exact size. Here are some practical approaches to help you confidently prepare for the big day. For the basics on measuring, please also see How to Measure Ring Size.

Ways to Quietly Estimate the Size

• Borrow a ring she wears regularly without her noticing, and measure its inner diameter
• Casually ask a family member or close friend for help
• Get a rough idea by holding hands or comparing with your own finger

Determining the Size from the Ring's Inner Diameter

If you know the inner diameter (in mm) of a borrowed ring, you can estimate the Japanese ring size, or "go" (inner circumference of about 47mm → approximately size 7; about 51mm → approximately size 11). However, even for the same person, the size may differ between the left and right hand or between fingers. If you borrow a ring worn on a finger other than the ring finger, keep this in mind as well.

Choosing with Resizing in Mind

Another approach is to prioritize simply giving the ring, with the plan to have it resized later. Before purchasing, it's a good idea to check with the store whether resizing is available, including the free range, number of times allowed, and which designs are eligible. Be aware that some designs, such as eternity rings, have limited resizing options.

Adjusting the Size Together Afterward

In recent years, it's become popular to express your feelings and present the ring during the surprise, then visit a store together afterward to adjust the size or make the official purchase. This way, her preferences can also be reflected, reducing the chance of mistakes. It's a recommended method that achieves both the "surprise" element and "her satisfaction with the final choice." You can find participating stores through our Store Search.