Ring Size Chart (US, UK and EU Sizes)

This ring size chart gives you US, UK and EU sizes in one place, with the exact diameter and circumference of every size. Buying a ring online is easy. Getting the size right is the hard part, and that is what this page fixes.

You can read your size straight off the ring size chart, measure your finger at home with a strip of paper, or lay a ring you already own on your screen. No printer, no appointment, no guessing.

Ring size chart and finder

Convert between US, UK and EU sizes, work out your size from a measurement, or check a ring you already own against your screen.

Tap a row to see that size in every system.

Selected size

US 7

US & Canada UK & Australia EU (ISO) Inside diameter Inside circumference

Canada and Mexico use US sizes. Australia, New Zealand and Ireland use UK sizes. Most of Europe uses the ISO number, which is the inside circumference in millimetres.

Getting the fit right

  • Measure late in the day. Fingers are slightly larger in the evening and when you are warm.
  • Check the knuckle. The ring must slide over it. If your knuckle is much wider, choose the size that fits over it.
  • Go up for wide bands. Bands wider than 6 mm feel tighter, so many people choose a quarter to half size larger.
  • Between two sizes? Pick the larger one. A ring that is slightly loose is easier to live with than one that pinches.

Sizes use the standard US, UK (BS 6820) and ISO 8653 scales. Some brands run up to a quarter size small or large, so check the brand's own chart when it has one.

How to Use This Ring Size Chart

Ring size chart showing US, UK and EU ring sizes with diameter and circumference

There are three ways to find your size here, depending on what you have in your hand right now.
1. You already know one size and need another. Open the Size chart tab and find your size in the US, UK, or EU column. Tap any row, and the corresponding system appears at the top.
2. You have a ruler, string, or a strip of paper. Open the Find my size tab and enter your measurement. The tool converts it into a ring size straight away.
3. You have a ring that already fits. Open the Check on screen tab, match a coin to your screen, then lay the ring on the circle.

How to Measure Your Ring Size at Home

Measuring ring size at home with a paper strip to use with the ring size chart

You do not need a ring sizer for this. A strip of paper works.
1.  Cut a thin strip of paper about 10 cm long and 5 mm wide. String works too, but paper is less stretchy, so it is more accurate.
2. Wrap it around the base of your finger. Keep it snug, not tight. You should still be able to slide it a little.
3. Mark where the ends overlap with a pen, then unwrap the strip.
4. Measure the length up to your mark in millimetres. That number is your finger’s circumference.

Enter that number in the Find my size tab above to find your size.

Two things that change the result:

  • Your knuckle. The ring has to pass over it. If your knuckle is much wider than the base of your finger, measure both and pick the size that slides over the knuckle without falling off the base.
  • Time of day and temperature. Fingers swell in heat and late in the day, and shrink when you are cold. Measure in the evening at normal room temperature for the most realistic fit.

Check Your Ring Size on Screen (Actual Size)

A printed ring size chart only works if your printer scales at exactly 100%, and most people never check that setting. The on-screen method skips the printer completely.

 

Here is how the Check on screen tab works:

  1. Calibrate once. Hold a coin or a bank card against the screen and move the slider until the outline matches it exactly. Every screen is a different size, so this step is what makes the result usable.
  2. Lay your ring on the circle. Move the second slider until the pink line sits just inside the ring’s inner edge.
  3. Read your size. US, UK and EU sizes all update as you move the slider.

This free online ring sizer is a quick way to check a ring you already own. It is not a replacement for a jeweller. For an engagement ring, or any ring you cannot return, confirm the size with a plastic ring sizer or in a shop first.

Average Ring Sizes for Women and Men

If you have nothing to measure and need a starting point, jewellers usually stock the middle of these ranges:

  • Women: most rings sold fall between US 5 and US 7, with US 6 to 6.5 being the most common.
  • Men: most rings sold fall between US 8 and US 10.5, with US 9 to 10 being the most common.

Treat these as a guess of last resort, not a measurement. Hand size, knuckle shape and band width all move the real answer. If you are ordering a surprise gift, an average size is only worth using when the shop has free returns or free resizing.

Why Ring Size Charts Don't Always Match

Look at three ring size charts and you may see three slightly different answers for the same size. There are three reasons for that, and none of them means one chart is wrong.

Rounding. US sizes are defined by the inside circumference of the ring. US 7 is about 54.4 mm around. The EU (ISO) system uses that circumference as the size number, so some charts round it to 54 and others to 55.

Different national systems. US and Canada use numbers. The UK, Australia, Ireland and New Zealand use letters. Most of Europe uses the ISO number. Japan, India and Switzerland each have their own scale. Letters and numbers never line up perfectly, so half steps appear.

The band itself. A wide or thick band takes up more room inside the ring, so it feels tighter than a thin band in the same size. Many people go up a quarter or a half size for bands wider than 6 mm.

The practical rule: use one ring size chart, measure carefully, and when a brand publishes its own chart, follow that brand’s chart.

Tips for the Perfect Fit

  • Measure at the end of the day. That is when your fingers are at their largest.
  • Measure three times. If two results agree, use that one.
  • Between two sizes? Go up. A slightly loose ring is easier to live with than one that pinches, and a jeweller can add a sizing bead later.
  • Cold hands, wrong number. Warm your hands first.
  • Think about the band width before you order, not after.
  • Check the return policy before buying, especially for gifts.

How to Find Someone's Ring Size for a Surprise Gift

Asking spoils the surprise. These methods do not.

Borrow a ring she already wears. Take one from the same finger of the same hand, measure the inside width with a ruler, then read the size off the ring size chart above. Fingers on the dominant hand are often a little larger, so note which hand the ring came from.

Trace the inside. If you cannot take the ring with you, place it on paper and draw carefully around the inside edge, then measure across your drawing.

Press it into soap or clay. Push the ring flat into a bar of soap and measure the inner circle it leaves behind.

Ask the right person. A sister, a best friend, or her mother usually knows, and they are better at keeping secrets than you might think.

Choose a forgiving style. Adjustable rings, open rings, and thin stacking bands are far more likely to fit on the first try, which is why they make safer gifts. Browse our best ring picks for ideas, or start with the ring guides if you are new to buying rings.

Should You Buy a Ring Sizer?

If you buy rings online more than once, yes. A reusable plastic ring sizer costs very little, works in about a minute, and removes the guesswork that causes returns. Look for one with a smooth edge that closes like a belt, and measure the finger you will actually wear the ring on.

See ring sizers on Amazon

Ring Size Chart FAQ

Are ring sizes universal? No. US and Canada use numbers, the UK and Australia use letters, and most of Europe uses the ISO number, which is the inside circumference in millimetres. The ring size chart above converts between all three.

Are ring sizes the same for men and women? Yes, the scale is the same. There is no separate men’s or women’s system. Men simply tend to wear larger sizes, so men’s rings are usually stocked from around US 8 upwards.

Do ring sizes come in half sizes? Yes, and many brands also offer quarter sizes. If a ring you want is only sold in whole sizes, order the larger one.

Do ring sizes vary by brand? The standard is the same, but manufacturing tolerances and band thickness differ, so the same size can feel slightly different from two brands. Always check the brand’s own chart when it publishes one.

Can your ring size change? Yes. Weight change, pregnancy, heat, cold, exercise and age all affect finger size. Many people are half a size larger in summer than in winter.

Are ring sizes measured in cm or mm? Millimetres. A US 7 is about 17.3 mm across the inside and about 54.4 mm around. The tool above accepts mm, cm or inches and converts for you.

Can a ring be resized later? Usually, if it is gold, silver or platinum. Rings made from tungsten, titanium, or ceramic normally cannot be resized, and eternity rings set with stones all the way around are difficult and expensive to resize. Get the size right the first time for those.

 

Bookmark this ring size chart before you order, and check your size once more on the day you buy. It takes two minutes and saves a return.

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