How to measure your ring size at home

The most reliable way to measure your ring size at home is to measure the inside diameter of a ring that already fits the same finger, then match it to a size chart. Measure in millimeters, at the end of the day when your fingers are warm, and size up slightly for wide bands. String and paper strip methods are a rough guide only, because they stretch and slip.

What is the most accurate way to measure ring size at home?

A ring you already wear comfortably on the same finger is your best reference. Lay it on a ruler with millimeter marks and measure straight across the inside edge, from one inner wall to the other. Do not include the metal itself. Measure twice, in two directions, and use the average.

Then compare your number with this US size reference:

• Size 5: about 15.7 mm inside diameter
• Size 6: about 16.5 mm
• Size 7: about 17.3 mm
• Size 8: about 18.1 mm
• Size 9: about 18.9 mm
• Size 10: about 19.8 mm

Each quarter size is roughly 0.2 mm in diameter. That sounds tiny, but on your finger you will feel it, which is why most of my rings, like the 3mm Gold Wedding Band, Comfort Fit, are offered in quarter sizes.

Why are string and paper methods often wrong?

Wrapping string or a strip of paper around your finger measures circumference, which can work in theory. In practice, string stretches, paper creases, and it is hard to pull either one to the same tension a solid ring would have. A difference of just 1 mm in circumference is close to half a size. If this is your only option, use a thin, non stretchy paper strip, mark it carefully, divide the length by 3.14 to get the diameter, and treat the result as a starting point rather than a final answer.

When is the best time of day to measure?

Fingers change size through the day. They are smaller in the morning and when you are cold, and larger after exercise, in heat, or after a salty meal. Measure in the late afternoon or evening at a normal room temperature, and measure more than once on different days if you can. If you get two results, the larger one is usually safer for comfort.

Does the width of the band change the size I need?

Yes. A wide band covers more of your finger, so it feels tighter than a slim band of the same size. As a general guide, bands of about 6 mm or wider often need a quarter to half size larger than you would choose for a thin ring.

The Link Statement Ring is a good example. At 7.70 mm wide, it sits on your finger very differently from a 3 mm band, so if you are between sizes, go up.

Comfort fit bands, which are rounded on the inside, can feel a touch easier to slide over the knuckle than flat inside bands. That is part of why they are so popular for wedding bands that you never take off.

What if my knuckle is bigger than my finger?

This is very common. Measure both the base of your finger and your knuckle. The ring needs to pass over the knuckle without force, but it should not spin freely at the base. Choose a size between the two, closer to the knuckle measurement, so it slides on with a gentle push and stays put once it is there.

How do I find the size for a surprise ring?

Borrow a ring she already wears on the same finger, measure it as described above, and return it before she notices. If it is a ring she wears on a different finger, remember that the dominant hand is usually a little larger. Open styles can also be more forgiving, like the Two Butterflies Wrap Ring, where two butterflies meet in an open wrap around the finger.

If you are shopping for an engagement ring and still deciding on the stone, my guide to pear vs oval diamond engagement rings walks through the shape decision.

Key facts for measuring ring size

• Measure the inside diameter of a ring that fits, in millimeters.
• Measure in the evening, at room temperature, more than once.
• Wide bands of about 6 mm or more often need a quarter to half size up.
• The ring should pass the knuckle with a gentle push and not spin at the base.
• String and paper are a rough estimate, not a final size.

Frequently asked questions

Is it better to size up or down if I am between sizes?

For most rings, size up, especially for wide bands. A ring that is slightly loose is more comfortable than one that pinches, and it can be adjusted more easily.

Are ring sizes the same in every country?

No. The US and Canada use numbers, the UK and Australia use letters, and much of Europe uses the inside circumference in millimeters. Measuring in millimeters lets you convert to any system.

Can I tell the studio my measurement in millimeters?

Yes. If you are unsure which size to pick, send the inside diameter or circumference you measured and the studio will help you choose.

Every ring at Margaret Krinetz Fine Jewelry, handmade in Tel Aviv, is made to order in 4 to 6 weeks, so getting the size right before the gold is cast matters. Take your measurement, then browse all rings or the wedding bands and choose the one you will want to wear every day.