Find Ring Size Without Asking: 7 Sneaky Methods

By Lucas Meyer · May 26, 2026

The Surprise Proposal Problem

You want to surprise them with a proposal — but you need their ring size first. Asking directly ruins the surprise. Here are 7 methods that jewelers recommend, ranked by accuracy.

Method 1: Borrow a Ring They Already Wear (★★★★★)

Accuracy: 95%+ if it's from their ring finger

How: Borrow a ring they wear on their left ring finger (or right ring finger — sizes are usually the same). Take it to a jeweler for sizing, or trace the inner circle on paper. Return it before they notice.

Risk: They might notice it's missing. Best for rings they don't wear daily.

Method 2: The Soap Impression (★★★★☆)

Accuracy: 90%

How: Press one of their rings into a bar of soap to create an impression. Take the soap to a jeweler for sizing. Works best with simple bands (not intricate designs).

Method 3: Ask Their Best Friend (★★★★☆)

Accuracy: 85% (depends on the friend)

How: Ask their best friend or sibling to casually find out. "I'm shopping for a ring — any idea what size she wears?" Most close friends either know or can find out naturally.

Risk: The friend might accidentally reveal the surprise.

Method 4: The String Method While Sleeping (★★★☆☆)

Accuracy: 70-80%

How: While they're sleeping, wrap a piece of string or floss around their ring finger. Mark where it overlaps. Measure the length and convert to ring size using a chart.

Risk: Waking them up. Fingers swell during sleep, so this tends to overestimate by half a size.

Method 5: Compare to Your Own Finger (★★★☆☆)

Accuracy: 65%

How: Slide one of their rings onto your own finger and mark where it stops. Take that measurement to a jeweler. Women's average ring size is 6-7.

Method 6: The Paper Strip (★★☆☆☆)

Accuracy: 60%

How: Cut a thin strip of paper. While they're distracted (watching a movie), wrap it around their finger and mark the overlap. Casual and low-risk but not very precise.

Method 7: Use a Ring Sizer App (★★☆☆☆)

Accuracy: 50-60%

How: Several apps let you place a ring on your phone screen to measure the inner diameter. Convenient but not very accurate due to screen calibration differences.

The Safety Net

If you're unsure, buy the ring slightly larger (you can always size down more easily than up). Most jewelers offer free resizing within 30 days. Average women's ring size: 6. Average men's ring size: 9-10.