How to Find Your Partner's Ring Size Without Asking
By Clint Casmiro, Co-Founder, Smiro Studio, Toronto · Updated September 27, 2026
Short answer: Borrow a ring they already wear on the same finger and have it measured, or trace its inside on paper. If you cannot, ask a friend or family member, or guess on the larger side. A ring can be resized after the proposal: with us it is $100 in person or $200 shipped.
You do not need to be exact. You need to be close, and on the right side of close.
How can I find their ring size without them knowing?
- Borrow a ring they wear on the ring finger of the same hand, and have any jeweller measure it. A $10 plastic ring sizer from Amazon works too.
- Trace it. Put the ring on paper and trace the inside circle, or press it into a bar of soap. Measure the inside diameter in millimetres.
- Ask a friend or sibling. They can bring it up while shopping, or already know.
- Check a ring on a different finger. Tell the jeweller which finger it came from so they can adjust.
- Compare to your own fingers while holding hands. Rough, but better than nothing.
- Size up if unsure. Going down is easier than going up.
What is the average ring size?
In North America most engagement rings fall between size 5 and 7. If you have nothing else to go on, 6 is a common starting point, but please use one of the tricks above first.
What if I get it wrong?
It happens all the time and it is fixable. Our resizing costs $100 dropped off or $200 shipped, and it keeps your warranty intact. Sizing beads, which help a ring sit straight on a finger with a bigger knuckle, are $150 dropped off or $200 shipped.
Can every ring be resized?
Most can. Eternity bands and fully engraved bands usually cannot be resized cleanly and may need to be remade, which costs more. If you are unsure of the size, choose a design that leaves room to adjust.
Want us to look at your idea?
A free 30 minute video call with Clint or Karina. Bring a photo, a budget, or nothing at all.
Book a free callSee our processQuestions we get about this
How do I secretly find out my girlfriend's ring size?
Borrow a ring she wears on the same finger and have it measured, or trace the inside of it on paper. A friend or family member can also help.
Is it better to guess a ring size too big or too small?
Too big. Making a ring smaller is simpler than stretching it.
How much does resizing cost?
At Smiro Studio resizing is $100 dropped off or $200 shipped. Sizing beads are $150 or $200.
Do you send a ring sizer?
No need. A plastic ring sizer is about $10 on Amazon, or any local jeweller can measure a finger in a minute.
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