Be Subtle

A surprise proposal leaves plenty of room for errors. Subtlety is your best friend! Be very smooth when asking her for her ring size and try slipping it in between another conversation. For example, you can ask her for her ring size with the pretext of purchasing a ring for your mother or sister – someone who has similar sized fingers. You could then actually go ahead and purchase an inexpensive ring and have her try it on to make sure it’s the correct size, and to provide some proof to your story.

Make her best friend your best friend

A girl’s best friend is like her own personal diary. Get her on your team, and if she doesn’t know her size right away, she can help you find out! A girl’s day includes all sorts of fun things, so ask her to slip in an engagement ring window shopping spree into the mix and have her professionally measured. A sure-shot method if the best friend can pull off being a professional actor for a day. 

Borrow One Of Their Rings

​A simple strategy, but definitely includes certain challenges. Make sure you grab a ring that is worn on a similarly sized finger. A tip would be to avoid grabbing one that holds sentimental value in order to avoid panic and distress.

Trace it

If borrowing a ring is off the charts, try tracing it out when she’s not around. Take a piece of paper and draw a circle on the inside and outside of the ring. Do it multiple times to make sure there are no errors and the circles are consistent. Usually, this is enough to figure out the size of the ring.

Make Use Of Experience

If she has a friend who is already engaged and would have similar sized fingers as your partner, have her make your partner try on her ring “just for fun”! Even if you don’t get an accurate size, you’ll unquestionably get a ballpark size. What’s more? You get a chance to ask her how she liked her friend’s ring to get an idea on the style of ring she may prefer.

Compare Fingers

Not the most accurate, but certainly the safest. When you hold hands next, try figuring out which of your fingers is similar sized to her ring finger. For example, her ring finger might be as big as your pinky.

Ask Your Partner

 Imagine a surprise fairy-tale proposal, but then the ring doesn’t fit. What a bummer! The easiest and most efficient way would be to just ask your partner! And, the element of surprise still persists because she won’t know when or how you’re going to propose!

If your partner doesn’t know their ring size, they can find it using our printable ring sizing guide.