Ring Size Chart and How to Measure Ring Size

Ring sizes

Not everyone’s finger grows to be the same size. Thus, not every ring is made to fit every finger. So, because you sink thousands of dollars on a new ring for your partner, you should at least try to sneak a peak at their finger’s circumference. Or you can rely on a ring size chart to figure out what size ring your lover should get.

Ring Size Chart

Rings are measured by circumference and diameter. The circumference of a ring refers to the outer edge of the ring (the portion that doesn’t make contact with your finger when worn). The diameter is the distance from one point to the opposite point on the inner edge of the ring.

In the US, ring sizes start at 3 and end at 13.5 (including half sizes). The following chart describes the circumference and diameter measurements of each ring size. Please note that this chart does not take into account the thickness of the band.

Ring SizeDiameterCircumference
314.1 mm44.2 mm
3.514.5 mm44.5 mm
414.9 mm46.8 mm
4.515.3 mm48.3 mm
515.7 mm42.3 mm
5.616.1 mm50.6 mm
616.5 mm51.9 mm
6.516.9 mm53.1 mm
717.3 mm54.4 mm
7.517.7 mm55.7 mm
818.1 mm57.0 mm
8.518.5 mm58.3 mm
919.0 mm59.5 mm
9.519.4 mm60.6 mm
1019.8 mm62.1 mm
10.520.2 mm63.4 mm
1120.6 mm64.6 mm
11.521.0 mm56.9 mm
1221.4 mm67.2 mm
12.521.8 mm68.5 mm
1322.2 mm69.7 mm
13.522.6 mm71.0 mm

Ring Size Variables

Ring Size Variables

Sizing a ring is no easy feat since there are so many things to take into account. So, if you are planning on buying a ring, here are the things you need to pay attention to.

Shape of the finger

Did you know that fingers come in all lengths and girths? As such, finding a ring of a specific size isn’t the only thing you should think about. The wearer must feel comfortable with the ring on their finger, which can be difficult to quantify.

See also  Unisex T-Shirt Size Chart

The next time you get an up-close look at your partner’s fingers, try and see how tapered they are. If their fingers are tapered toward the fingertips, there’s a good chance the ring will slip off without much coaxing. On the other hand, if their fingers are pretty wide, then you’ll need to find a ring that will slip through the widest joint.


The width of a band refers to its height when you stand it upright on a flat surface. Wider rings will take up more of the wearer’s fingers, which can make it uncomfortable to wear while gripping an object. Over time, the wearer might feel that the ring is restricting blood flow to their finger. This might not be too huge of a problem for promise rings or regular everyday finger accessories.

On the other hand, if you’re on the hunt for the perfect engagement ring, look for a thin band instead. Not only does a thin band look classier, but the center stone will stand out a lot more!


The thickness of a band refers to the distance between the inner and outer circumferences. Thicker bands will force the wearer’s fingers apart, whereas thinner bands will most likely be “concealed” by the taper of their finger. The general thickness for engagement rings is 1.5 millimeters for women and 1.8 millimeters for men.


The circumference of a ring is taken by measuring its outer perimeter. When sizing the circumference, you should take note of the thickness of the band (a thicker band equals a longer circumference) and the girth of the wearer’s finger.


Finally, the diameter of a ring is the distance between 2 opposite points along the inside perimeter of the ring. It will be affected by the girth of the wearer’s finger.

See also  Everything You Need to Know About Tote Bag Size

How to Size a Ring?

Now that we know what variables to look for, we can begin the ring-sizing process. There are a couple of methods you can try based on what supplies you have on hand.

Floss or string

Floss or string

  1. Cut a piece of floss or string that is roughly the length of your finger. It doesn’t have to be too long since we only want to measure the girth of your ring finger.
  2. Take the piece of floss or string and wrap it around your finger, making sure that it’s as low as it can go (toward the base).
  3. Mark the meeting point between both ends of the string with a marker or pen.
  4. Flatten the piece of floss or string and measure it with a ruler.
  5. Compare the measurement to the chart above (use the diameter column as a reference).

Make sure not to tug too hard on the piece of floss or string when tying it around your finger. Floss and string can be stretchy, and if it stretches too far, you might end up with a ring that’s several sizes too large.

Measuring tape

measure Tape

  1. Take the measuring tape and wrap it around your ring finger, making sure it’s as low toward the base as it can go.
  2. Mark where the ends of the measuring tape meet.
  3. Compare that measurement to the ring size chart above (use the diameter column).

Again, a measuring tape can be a bit flexible, so try not to tug on it too hard.

How to Size a Ring Without Your Partner Knowing

How to Size a Ring Without Your Partner Knowing

The real problem when sizing a ring is trying to do it discreetly. Asking your partner for their ring finger size would defeat the whole purpose of springing a surprise engagement on them. So, here are some tips you can try to get your partner’s ring finger size without them being the wiser.

See also  Fat Quarter Dimensions (Size Guide)

Borrow a ring from their jewelry box

The rings they own can be a great reference for sizing an engagement ring. Make sure to take a ring that your partner doesn’t keep a close eye on (they’ll know when it’s missing), and make sure it’s a ring that they wear frequently. The last thing you want is to measure a ring that they used to wear as a high school freshman!

Get their measurements while they’re asleep

Sure, this sounds sort of creepy, but it only takes a few seconds. To pull this trick off, make sure there’s plenty of light so you won’t have to rely on the bright flashlight of your smartphone (that’ll wake them up!). Quickly get their ring finger diameter measurement, record the figure somewhere, and let them go back to sleep undisturbed.

By the way—did I mention which finger is the ring finger yet? It’s the finger next to their pinky. Don’t mess up and measure their thumb by mistake!

Ask someone who knows

Desperate times call for desperate measures. You might have to ask their close friends or parent what their ring size is. Perhaps they’ll know because they once lent a ring to them. Just make sure the person you ask isn’t a blabbermouth, or the whole surprise engagement would be pointless.

Can You Resize a Ring?

Yes, you can. If you somehow messed up in finding the right ring size, you could always take it back to the jeweler to get it refitted. Of course, this is assuming that they accepted your proposal!

However, please note that ring sizes can only be brought up or down by 1 to 2 sizes. So, if you made a colossal mistake and chose a size 13 ring for a size 7 finger, tough luck.


Baron Cooke has been writing and editing for 7 years. He grew up with an aptitude for geometry, statistics, and dimensions. He has a BA in construction management and also has studied civil infrastructure, engineering, and measurements. He is the head writer of measuringknowhow.com

Leave a Reply

Your email address will not be published. Required fields are marked *