mPlanning a proposal or a surprise gift is exciting, but it can get tricky if you don't know your partner's ring size. Asking directly might ruin the surprise, and guessing? Well, that can be risky, especially when you're spending a small fortune. Luckily, there are clever ways to figure it out without them ever knowing.
Here's how to find out someone's ring size without asking them.
Look at The Rings They Already Have
One of the easiest ways to get an idea of someone's ring size is by looking at the rings they already wear.
- Notice the finger they usually wear rings on.
- Borrow a ring (from the correct finger) for a short time on the pretence of admiring or photographing it and take it to a jeweller or use a ring sizer at home.
Our client James wanted to propose to Emily but didn't know her size. He remembered she wore a gold band on her ring finger. He discreetly borrowed it when she went out and used a ring sizer at home. He sent the results over to us and we successfully made sure the fit was perfect when he proposed the following week.
Even if it's a ring worn on another finger, you can still get a rough measurement and adjust using a size chart.
Trace or Measure a Ring
If borrowing a ring isn't possible, don't panic. You can still figure it out with a little creativity.
- Place the ring on a piece of paper and gently trace the inside circle. No need to press too hard, just a clear line will do.
- Measure the diameter of the circle in millimetres or centimetres.
- Compare your measurement to a ring size chart to get an approximate size. It's always safer to go up a size so the fit is more comfortable.
This trick works perfectly if you can access their jewellery for just a short moment, or if they happen to leave a ring somewhere safe to measure. It's a subtle, low-pressure way to get the information you need without them noticing.
Hannah wanted to surprise her girlfriend, Mia, with a custom engagement ring. Mia left her ring on the dresser one night. Hannah traced it, measured the diameter, and used an online chart to figure out the size. We made a ring Mia loved, and it fit perfectly.
Use Technology
Technology can help you figure out a ring size without asking.
- Ring size apps: Some apps allow you to place a ring on your phone screen or use augmented reality to measure the finger.
- Photo measuring: Take a clear picture of the person's hand next to a ruler or a standard-sized object. Some apps or online calculators can estimate their ring size from this image.
Luke wanted to propose to his partner Harriet on vacation. He had a photo of her hand from a recent beach day. Using a ring size app, he estimated her ring size without her knowing and sent the results to us. We created a custom engagement band, and it was an accurate fit.
Ask a Trusted Friend or Family Member
If you're worried about messing up, a friend or family member might already know their ring size or could subtly find out without giving away the surprise. Sometimes, people casually mention their size in conversation or joke about rings fitting on certain fingers.
Mark asked his sister to help him secretly figure out his girlfriend's ring size. She remembered seeing a ring she tried on last Christmas. With that information, Mark ordered the perfect engagement ring from Vinny & Charles without letting the secret out.
FAQs About Finding Someone's Ring Size
Q: What if I'm really not sure about their size?
A: If you're stuck between sizes, it's usually safer to go a little bigger. A ring that's slightly loose can be resized later, but a tight one… that's a bit more challenging, but it's not impossible.
Q: Are those ring size apps actually any good?
A: Most of them are surprisingly accurate, as long as you follow the instructions. If you want, you can double-check with a size chart just to be extra safe.
Q: What if they never wear rings?
A: Totally doable. Here's a few tricks:
- Compare their fingers to yours or a friend's for a rough idea.
- Ask someone close to them who might already know.
- Snap a photo of their hand next to a ruler or standard object and use an app or online tool to estimate the size.
Even without a ring on hand, you can still get a pretty solid estimate.
Figuring out someone's ring size without asking doesn't need to be stressful. With a little creativity, some observation, and handy tools like apps, charts, or a ring sizer, you'll get it right.
At Vinny & Charles, we love making these moments easier. Need a hand? Our team's always happy to help.

