Reviewed by Yoona's in-house jewelry experts
Short answer: the most reliable at-home methods are measuring a ring you already own or using a proper ring sizer, string and paper methods work but are the least precise. Measure at the end of the day, and if you're between sizes, size up rather than down.
Method 1: Use a Ring You Already Own
Quick answer: Print a to-scale ring size chart, then place an existing ring that fits the intended finger over each circle until the inner edge lines up exactly. This is one of the most accurate at-home methods since it uses a real, known fit.
This works best with a ring already worn on the same finger you're sizing for, since ring size can vary noticeably between fingers and even between hands for the same person.
Method 2: The String or Paper Strip Method
Quick answer: Wrap a thin strip of paper or string around the base of the finger, mark where the ends meet, then measure that length in millimeters against a ring size chart.
This is the most accessible method since it needs no special tools, but it's also the least precise, string can stretch slightly and paper can shift while wrapping. Measure at the end of the day when fingers are at their largest for the most reliable result.
Method 3: Order a Ring Sizer
Quick answer: A plastic ring sizer gives the most reliable at-home measurement short of an in-person fitting. Yoona sends free ring sizers on request, just reach out and we'll mail one to you.
This is worth doing specifically for a surprise proposal, where you can't simply ask, but need real accuracy rather than a guess. A ring sizer removes the guesswork of string stretch or paper shifting entirely.
Why Finger Size Fluctuates
Quick answer: Temperature, time of day, sodium intake, and physical activity can all cause a finger to measure slightly larger or smaller. Measuring under consistent, favorable conditions, warm hands, end of day, helps avoid an inaccurate result.
Cold hands cause fingers to shrink temporarily, which is why measuring first thing in the morning or after being outside in cold weather tends to produce a size that reads smaller than a finger's typical resting size. High sodium intake and exercise can cause temporary swelling in the other direction. None of this means sizing is unreliable, it just means consistency in when and how you measure matters more than most guides mention.
If You're Between Sizes
Quick answer: Size up rather than down. Resizing a ring smaller is generally simpler and less expensive than resizing it larger, so starting slightly big gives you more flexibility later.
This is standard, well-founded jewelry advice, not just a rule of thumb. Reducing a band's size involves removing a small section and resoldering, a routine adjustment for most designs. Increasing size means adding metal, which is more involved and isn't possible at all for some styles, like eternity bands with stones set all the way around.
International Ring Size Conversion Chart
Quick answer: Ring sizing systems vary by country, US, UK, European, and Japanese sizes don't share the same numbering, so always convert carefully when shopping or gifting across regions.
| US Size | UK | Europe | Japan | Inside Diameter (mm) |
|---|---|---|---|---|
| 4 | H | 47 | 7 | 14.9 |
| 5 | J½ | 49 | 9 | 15.7 |
| 6 | L½ | 52 | 11 | 16.5 |
| 7 | N½ | 54 | 14 | 17.3 |
| 8 | P½ | 57 | 16 | 18.1 |
| 9 | R½ | 59 | 19 | 18.9 |
| 10 | T½ | 62 | 21 | 19.7 |
| 11 | V½ | 64 | 24 | 20.5 |
Additional Sizing Tips
- Avoid measuring with cold hands, fingers temporarily shrink.
- Check fit by sliding a reference ring over the knuckle, it should pass with slight resistance, not slide freely or require force.
- Wider bands fit more snugly than thin ones, size up slightly for a chunky band compared to a thin one at the same measured size.
Frequently Asked Questions
How accurate are at-home methods compared to a jeweler?
Very close for most people, especially using an existing ring or a proper sizer. Complex or unusually shaped fingers may benefit from an in-person fitting for full confidence.
What if I'm sizing for a surprise proposal?
Borrow a ring worn on that finger if possible and use it with a sizing chart, or ask someone close to the person to help discreetly. A free ring sizer request works well here too, once you have a reference ring to test it against.
Does ring width affect what size I should order?
Yes, wider bands feel tighter at the same numeric size, sizing up slightly for a wide band compared to a thin one is a common and reasonable adjustment.
Yoona's Sizing Support
We offer complimentary resizing within 90 days on most rings, along with free ring sizers on request for anyone who wants extra confidence before ordering. Reach out anytime if you're unsure.
