So, you’ve scrolled through their Pinterest boards, taken note of their jewelry style, and maybe even gotten a tip or two from friends. But now, as you start searching for the perfect engagement ring, one tricky question stands in the way: What’s their ring size? Don’t panic! Unless you’re already a jewelry expert, you might not have realized rings are sized just like shoes. The good news is—we’ve got you covered. Here’s your complete guide on how to measure ring size accurately, along with some insider tips to make sure your engagement ring fits like a dream.

Are Ring Sizes Standard?

The short answer: yes and no. Women’s ring sizes usually range from 3 to 9, with the most common being 5–7. Men’s rings, on the other hand, typically fall between sizes 6 to 13, with 8–11 being the average. But here’s the catch—choosing a “popular” size is risky, like buying shoes without knowing the size. You might get it right, but chances are it’ll either be uncomfortably tight or way too loose. And no one wants a ring slipping off (or stuck so tight it needs to be cut off!).

How Jewelers Measure Ring Size

When professionals measure ring size, they usually rely on two methods:

1. Measuring an existing ring – Jewelers use a mandrel, a tapered metal stick with size markings, to find the exact measurement of a ring.

2. Measuring your finger directly – This involves sliding pre-sized metal bands onto your finger until they find the best fit.

The second option is the most accurate, but it can spoil the element of surprise if you’re planning a secret proposal. Don’t worry—we’ve got solutions for that later.

Why Different Jewelers Give Different Sizes

Here’s the tricky part: not every jeweler measures ring sizes the same way. Just like clothing brands have different size charts, jewelers often use slightly different tools. Mandrels may vary, sample bands may differ in thickness, and even measurement techniques can cause slight inconsistencies. That’s why it’s always best to have your size confirmed by the jeweler who will be crafting your final engagement ring.

Band Width and Ring Style Affect Sizing

Did you know the style of ring can change your size preference?

• Thin bands often feel looser, so you might size down slightly.

• Wider bands (4mm–6mm) feel snugger, so you may need to go up half a size.

• Stacked bands (wearing multiple rings together) also require sizing up.

One important note: eternity bands cannot be resized. Because the diamonds (or gemstones) go all the way around, jewelers can’t adjust them later. This makes it extra important to get the right size the first time.

Why Finger Sizes Fluctuate

Finger sizes can change throughout the day—or even with the weather! Heat, cold, salty foods, or exercise can all cause your fingers to swell or shrink. That’s why you should measure your finger when it’s at a “normal” state: average temperature, average activity.

If you have large knuckles but slimmer fingers, you’ll need a ring that slips over the knuckle but doesn’t spin once it’s on. In this case, jewelers can add small “speed bumps” inside the band to help keep it in place.

How to Measure Ring Size in Secret

Planning a surprise proposal? No problem. Here are some sneaky ways to measure their ring size:

1. Borrow a Ring They Already Wear

Find a ring they wear often (and on the correct finger if possible). Use a printable ring size chart to match the inner edge with the closest circle. Just remember—different fingers are different sizes.

2. Use a Plastic Ring Sizer

Some jewelers (and even online stores) offer free ring sizers. These zip-tie-like tools loop around the finger and show the size. They’re simple and accurate, though they don’t always include quarter sizes.

3. DIY Ring Sizer with String or Floss

If you’re in a pinch, wrap a piece of string around the finger, mark where it overlaps, and measure the length in millimeters. Be cautious—this method leaves room for error, so it’s best as a backup.

Conclusion

Getting the right ring size is essential for comfort and security. Whether you measure with a jeweler, use a printable chart, or sneakily borrow one of their rings, always double-check before ordering. After all, a perfect engagement ring deserves a perfect fit.