You've found the ring, or you're about to design it, but there's a problem: you don't know your partner's ring size, and asking would ruin the surprise. This is one of the most common challenges in planning a proposal.
This guide covers practical, discreet ways to figure out a ring size without measuring your partner's finger directly, how accurate each method is, and what to do if you're not sure.
Method 1: Borrow a Ring They Already Wear
This is the most reliable method.
- Find a ring your partner wears on their left ring finger, or on the ring finger of their right hand (with an adjustment, see below).
- Borrow it briefly and bring it to a jeweler, who can size it on a mandrel in seconds.
- Return it before it's missed.
Accuracy tip: Make sure the ring is worn on the right finger. A ring from the middle finger or pinky won't help. Right and left hands can differ slightly. The dominant hand is often a little larger.
Method 2: Trace or Measure a Ring
If you can't take the ring out of the house:
- Trace the inside of the ring on paper with a fine pen, both inside and outside edges.
- Measure the inside diameter with a ruler in millimeters, edge to edge.
- Press the ring into soap or clay to make an impression of the inside.
Bring the tracing or impression to a jeweler. It's less exact than the ring itself but can get you close.
Method 3: Slide a Ring Onto Your Own Finger
Slide your partner's ring onto one of your fingers and mark where it stops with a pen. A jeweler can measure your finger at that spot. This is a rough estimate but useful in a pinch.
Method 4: Ask a Friend or Family Member
A close friend, sibling, or parent might know your partner's size. They might also be able to casually bring it up, like suggesting a fun trip to try on rings "just for fun."
Method 5: Use a Cover Story
- Gift a different ring first. A birthday or holiday ring sized at a store reveals the size.
- Shop for "someone else." Ask your partner to try on rings for a friend's or family member's gift.
- Talk about rings casually. Some couples discuss sizes long before a proposal.
Method 6: Sizing While They Sleep
Some people try wrapping string around a sleeping partner's finger. It's risky and not very accurate. String can stretch, and fingers swell during sleep. If you try it, use a thin, non-stretchy strip of paper and treat the result as a rough estimate.
Method 7: Educated Guess
If all else fails, an educated guess can work, since most rings can be resized after the proposal. Consider your partner's build and hand size compared to someone whose size you know, and their existing rings. A jeweler can help you estimate.
If You Have to Guess, Guess Larger
A ring that's slightly large can be worn carefully until it's resized. A ring that's too small may not fit over the knuckle at all, which can make the proposal moment awkward. Sizing down is also usually simpler than sizing up.
Rings That Are Hard to Resize
If you're unsure of the size, avoid ring styles that are difficult to resize, such as:
- Full eternity bands with stones all the way around
- Tension settings
- Tungsten, titanium, and other alternative metals
- Rings with patterns all the way around
A solitaire or a ring with a plain section at the bottom is the safest choice when you're guessing.
Ring Size Factors to Keep in Mind
- Temperature - fingers swell in heat. Arizona summers can make a snug ring tighter.
- Time of day - fingers can be slightly larger in the evening.
- Band width - wider bands fit tighter; you may need a slightly larger size.
- Knuckles - a ring must slide over the knuckle.
For more details, see our ring sizing chart guide.
After the Proposal: Get It Professionally Sized
Once the ring is on their finger, schedule a professional sizing. A jeweler will measure the finger in the same width as the ring and resize it if needed. Many straightforward sizings can be done the same day. Learn about ring resizing.
Planning a Custom Ring Without the Size
If you're designing a custom engagement ring, let us know you're unsure of the size. We can design with resizing in mind so adjusting after the proposal is easy.
Get Help With Ring Sizing in Mesa
Brilliant Jewelry is a fourth-generation, family-owned private jeweler at 1237 S Val Vista Dr Ste 204, Mesa, AZ 85204. Bring a borrowed ring, a tracing, or just your best guess, and we'll help you get the size right before or after the big moment. Read our engagement ring buying guide.
Book a discreet ring sizing consultation or call or text (480) 331-8652.