Engagement season has just begun! Between Thanksgiving and Valentine’s Day, nearly 40% of all brides get engaged with Valentine’s Day being the most popular and Christmas Day coming in at number 2. Whether or not you’re getting your future bride a Tiffany & Co. diamond ring, you can still easily get her ring size without her knowing. Simply download the Tiffany & Co. iPhone app and place your girlfriend’s ring on the ring sizer. Scroll up/down until the ring matches the ring on the screen.

Learn about the 4Cs, browse their gorgeous ring gallery for ideas, and see actual carat sizes.