Why Ring Size Matters More Than You Think
A ring that's half a size too large will spin on the finger all day. A ring that's half a size too small cuts off circulation. Resizing is possible for most designs but costs $50-$150 and can take 1-2 weeks — time you may not have before a proposal or wedding. Getting the size right the first time matters.
Ring sizes in the US use a numerical scale from 3 (smallest adult) to 13+ (largest). The average women's size is 6-7. The average men's size is 9-10.5. Your size will vary based on which finger, which hand, and the width of the band (wider bands need a slightly larger size).
Method 1: Use an Existing Ring (Most Accurate)
If the wearer already owns a ring that fits the correct finger, this is the most reliable method. Here's how:
- Borrow a ring they wear on the same finger the engagement ring will go on.
- Place the ring on a flat surface.
- Measure the inner diameter across the widest point in millimeters.
- Compare to a ring size chart.
For a 16.5mm inner diameter, US size 6. 17.3mm = size 7. 18.1mm = size 8. 19.0mm = size 9. 19.8mm = size 10.
Method 2: String or Floss Method
A simple, no-tools method that works on your own finger:
- Cut a piece of string or floss 6 inches long.
- Wrap it snugly (not tight) around the base of the finger.
- Mark the point where the string overlaps with a pen.
- Measure the marked length in millimeters with a ruler.
- Match to a circumference chart: 51.8mm = size 6, 54.4mm = size 7, 57.0mm = size 8, 59.5mm = size 9, 62.1mm = size 10.
Tip: Do this in the evening. Fingers swell 3-5% during the day from heat and activity. Measuring in the morning gives you a smaller size than you'll actually want.
Method 3: Printable Ring Sizer
Most jewelers provide a printable paper sizer you can download. Here's the key: print at 100% scale (not "fit to page") and verify the scale with a ruler before measuring. Even a 2% scaling error throws the size off by a full number.
Method 4: Order a Physical Ring Sizer
Most online jewelers, including Omour, will ship a free plastic ring sizer on request. It's a belt-style sizer with a series of numbered notches. You slide it on, pull it snug, and read the number at the base of the finger. More accurate than string, more reliable than a printable — and free. Request one at checkout or via our contact page.
Method 5: Measure an Existing Ring with a Mandrel
If you can get to a jeweler briefly, ask them to measure an existing ring on a ring mandrel (a tapered metal cone marked with sizes). Takes 10 seconds and is the single most accurate method. Most jewelers do this for free.
The Method to Avoid: Guessing From Photos
Looking at photos of their hand and estimating is not a method. Finger thickness varies far more than photos suggest. Even people who know each other well misjudge ring size by 1-2 full sizes when guessing visually.
What to Do If You Don't Know Their Size (Proposal Edition)
If you're planning a proposal and can't directly ask, here are the least suspicious ways to get their size:
- Borrow a ring from their jewelry box — one they wear on the ring finger — and take it to a jeweler for measurement. Return it the same day.
- Ask a close friend or family member to find out casually.
- Compare finger size against your own by holding hands (a rough indicator, not exact).
- Propose with a ring deliberately sized to your best estimate, knowing that resizing after the proposal is expected and easy for most designs.
The fourth option is more common than people think. A slightly-off size is completely normal for a surprise proposal, and resizing is covered free on every Omour ring for the first year. Learn more about our custom rings and resizing service.
Ring Size Chart (US / UK / EU)
| US | UK | EU | Inner Diameter (mm) | Circumference (mm) |
|---|---|---|---|---|
| 5 | J 1/2 | 49 | 15.7 | 49.3 |
| 6 | L 1/2 | 52 | 16.5 | 51.8 |
| 7 | N 1/2 | 54 | 17.3 | 54.4 |
| 8 | P 1/2 | 57 | 18.1 | 57.0 |
| 9 | R 1/2 | 59 | 19.0 | 59.5 |
| 10 | T 1/2 | 62 | 19.8 | 62.1 |
| 11 | V 1/2 | 64 | 20.6 | 64.6 |
Frequently Asked Questions
How do I measure my ring size at home?
The most accurate home method is measuring an existing ring they already wear on the correct finger: place it on a flat surface and measure the inner diameter in millimeters. 16.5mm = US size 6, 17.3mm = size 7, 18.1mm = size 8.
What's the average ring size for women and men?
The average women's ring size in the US is 6-7 (inner diameter 16.5-17.3mm). The average men's ring size is 9-10.5 (inner diameter 19.0-20.2mm).
Should I measure ring size in the morning or evening?
Measure in the evening. Fingers swell 3-5% during the day from heat, salt, and activity. A ring sized from a morning measurement will feel tight by afternoon.
Can a ring be resized after purchase?
Yes, most engagement rings can be resized up to 2 sizes in either direction. Resizing typically costs $50-$150 and takes 1-2 weeks. Omour offers free resizing for the first year on every custom ring.
What if I guess the ring size wrong for a proposal?
A slightly-off size is completely normal for a surprise proposal. Most engagement rings can be resized up to 2 sizes after the proposal, and Omour covers resizing free for the first year.