How to Find the Right Ring Size

Buying or ordering a ring online is easier when you know your size. This guide shows simple ways to measure at home, explains how sizing systems differ and covers the factors that can make a ring feel too tight or too loose.

Why ring size matters

A ring that is too loose can slip off or spin, while one that is too tight is uncomfortable and hard to remove. Because some designs, such as full eternity bands, are difficult to resize, it helps to get the size as close as possible before you buy.

Method 1: Measure an existing ring

If you own a ring that fits the intended finger well, this is often the easiest method.

1. Choose a ring that fits comfortably on the same finger and is similar in width.
2. Measure the inside diameter across the widest point of the inside of the ring, in millimetres.
3. Compare your measurement with the size chart used by the jeweller you are buying from.

You can also measure the inside circumference by laying the ring on a ruler or marking its inner edge on paper.

Featured Piece

Kohinoor Gems Recommendation

Explore this piece in the Kohinoor Gems store — lab-grown diamonds, free shipping over $250 and code WELCOME10 for 10% off your first order.

View in Store

Method 2: Use a strip of paper or string

1. Cut a thin strip of paper or a piece of non-stretch string.
2. Wrap it around the base of the finger.
3. Mark the point where the ends meet.
4. Lay it flat and measure the length in millimetres. That is your finger circumference.
5. Compare it with a size chart.

Do this a few times and use the average, because it is easy to pull the strip too tight or leave it too loose.

Method 3: Use a printable or physical sizer

Many jewellers offer a printable guide or a physical ring sizer. A plastic or metal sizer that you can slide over the knuckle is generally more reliable than paper, but check that it matches the sizing system the retailer uses. If you are buying an engagement ring, a visit to a jeweller who can measure with proper sizing tools is also an option.

Understanding sizing systems

Ring sizes are not the same worldwide. The United States and Canada use numeric sizes, such as 6 or 7. The United Kingdom and Australia use letters, such as N or P. Many European countries use circumference in millimetres. Always check which system a retailer uses and use their chart. As a reference point, a US size 7 has an inside diameter of about 17.3 millimetres, but you should rely on the specific chart provided by the seller you are buying from.

Tips for a more accurate result

• Measure at the end of the day. Fingers can be slightly larger later in the day and when warm.
• Avoid measuring when cold. Cold fingers can shrink and lead to a size that is too small.
• Consider your knuckle. If your knuckle is larger than the base of your finger, choose a size that passes over the knuckle but is not loose at the base.
• Measure more than once. Repeat on different days if possible.
• Think about the hand. Your dominant hand can be slightly larger than the other.

Does ring width change the size you need?

Yes. Wider bands tend to feel tighter than narrow ones. If you are choosing a wide band, many people go up a little, for example by a quarter or half size. If you are unsure, ask the seller for guidance on that particular style.

What if you are buying a surprise gift?

Borrow a ring the person already wears on the correct finger, trace the inside on paper or measure the diameter, and return it without them noticing. Another option is to ask a friend or family member who might know. If you cannot be certain, ask about the seller's resizing policy before you buy.

When a ring needs resizing

Many rings can be made larger or smaller by a jeweller, but there are limits. Eternity bands with stones all the way around, some intricate designs and certain metals or finishes can be harder to resize. Ask about resizing options, the cost and any time limit before you purchase.

Signs your ring fits well

A good fit slides over the knuckle with a little resistance and sits snugly without leaving a deep indent. It should not spin freely or fall off when you lower your hand. If it feels tight in the morning or in warm weather, you may want to adjust the size.

Next steps

Once you have your size, compare it with the seller's chart and check their return and resizing terms. You can then browse our rings with more confidence.