Borrow one of their rings (without them knowing)
This may sound a little sneaky, but if you can manage to borrow one of your partner's rings without them noticing, you'll have a good chance of finding out their ring size. Be careful not to take a ring that they wear all the time, as they may notice its absence. Try to pick a ring that you haven't seen them wear in a while and take it to a jeweler to have it sized.
Use a string
If you can't manage to sneakily borrow one of their rings, you can try using a piece of string to measure their finger. Wait until they're asleep or distracted and wrap the string around their finger, marking where it overlaps. Take the string to a jeweler and they should be able to tell you the size of your partner's finger.
Play a game of Twister
Invite your partner over for a game of Twister and make sure to grab a close-up of their hand when they're reaching for a color on the board. You can use this photo to help determine their finger size. Just make sure to act casual and don't let on that you're up to anything suspicious.
Ask their friends or family members
This is a more direct approach, but if you can discreetly ask your partner's friends or family members for their ring size, you might get lucky. Just make sure that the person you're asking can keep a secret, as you don't want to ruin the surprise.
Use a ring sizing chart
There are plenty of printable ring sizing charts available online that you can use to estimate your partner's ring size. Just make sure to print the chart out at the correct scale, otherwise your measurements may be off.
Now that you have a few ideas on how to determine your partner's ring size without them knowing, it's time to get creative! Remember, the key to a successful surprise proposal is making sure your partner feels loved and cherished, regardless of the size of the ring. Good luck and have fun!
