Ring Sizing Guide

Getting your ring size right - before the sparkle steals your heart

Not sure what ring size you are? You’re not alone. Ring sizing can feel a bit confusing, especially if you’re buying online or choosing a surprise gift. The good news? There are several easy ways to work out your size - and most rings canbe resized if needed.

Ring Sizing Guide

Find your size instantly

Measure the circumference of your finger and enter it below — we'll tell you your exact UK ring size in seconds. No chart-reading needed.

  1. Wrap a thin strip of paper around the base of your finger
  2. Mark where the paper overlaps and measure the length in mm
  3. Enter the measurement below to get your UK ring size
Ring size calculator

Enter your finger measurement below

Your UK ring size:

Ring Size Conversion Chart (UK to US & EU)

Browse the full UK ring size chart, including half sizes from G to Z. Switch between women's and men's sizes using the tabs below.

Ring Size Conversion Chart (UK to US & EU)
Internal Diameter (mm) UK Size (Letter) US Size EU Size (mm)
14.5 J 4.75 49
14.8 K 5.25 50
15.2 L 5.75 52
15.6 M 6.25 53
16.4 N 6.75 55
16.8 O 7.25 57
17.2 p 7.75 58
17.4 Q 8.25 60
18 r 8.75 61
18.4 s 9.25 63
19 T 9.75 65
How does ring sizing work at Charles Fish?

How does ring sizing work at Charles Fish?

Every ring at Charles Fish includes its size in the product specification, so you always know exactly what you're buying before you check out.

What type of ring sizing does Charles Fish use?

Charles Fish uses UK ring sizing, which is shown as a letter, for example, K, L, M or N. This is the standard sizing system used by jewellers across the UK and Ireland.

Buying as a surprise gift?

Don't worry – all rings come with 30-day free resizing. Buy with confidence and sort the perfect fit once it's been gifted.

Measuring For A Ring At Home

Invest in a ring sizer

If you want the most reliable at-home option, we suggest ordering a plastic or metal ring sizer. They’re inexpensive, reusable, and give you a very accurate result.

Can I use an app to measure my ring size?

Some apps can estimate ring size using your phone camera, but results can vary. We recommend confirming with a physical sizer or in store.

Visit a Charles Fish store

Our team can measure your finger in store for the most accurate fit.

Download and print our ring sizer at home. Follow the instructions carefully for the best results.

Measure with string

Wrap a piece of string around your finger, mark where it overlaps, then measure the length against our size chart.

Why are UK ring sizes letters?

Why are UK ring sizes letters?

UK sizes are based on the inner circumference of the ring, measured in millimetres, and are traditionally shown as letters rather than numbers. Each half size represents a very small difference, helping jewellers achieve a precise fit.

If you’re more familiar with US or European sizing, you can easily compare them using the chart:

Tip: If you’re between sizes, it’s often best to size up slightly — especially for wider bands

Frequently Asked Questions

Yes, there are ring-sizing apps that use your phone screen to help you measure an existing ring. These can be useful as a starting point, but they’re not always 100% accurate, so it’s best to double-check with another method if you can.

You can. Wrap a piece of string or a thin strip of paper around the base of your finger, mark where it overlaps, then measure the length with a ruler. This gives you a circumference you can match to a ring size chart. Just don’t pull it too tight — comfort is key.

Absolutely. Visiting a local jewellery shop is one of the best ways to get an accurate size. A jeweller can measure your finger properly and take into account things like knuckle size and band width.

If you have a ring that fits the finger perfectly, you can measure its inner diameter or take it to a jeweller to be sized. This is often the easiest and most accurate method.

Sometimes, yes. As a rough guide:

  • If your middle finger is a size L,
  • The finger to the left is often about L – ½ size,
  • The finger to the right is often about L + ½ size.

This isn’t exact, but it can be helpful if you’re estimating. You can also compare your dominant hand with your other hand: correlating fingers will be similar but with the fingers on theĀ  hand you do most things with (i.e., your writing hand) being around ½ to 1 size bigger than the either.

Most plain metal rings, including gold, platinum and silver, can usually be resized up or down by one to two sizes without any issues. Simple bands are the easiest to adjust.

Some rings are very difficult or impossible to resize, including:

  • Eternity rings with stones all the way around
  • Rings with a design all the way around eg plait bands
  • Very delicate vintage rings that could be damaged
  • Rings with complex settings or patterns that would be disrupted
  • Rings featuring hollow metal throughout

A jeweller can always advise on a case-by-case basis.

There are a few common ways resizing is done:

  • Taking metal out to make the ring smaller
  • Adding metal to make the ring larger
  • Adding sizing balls inside the band to improve fit without changing the size

The method depends on the ring style and how much adjustment is needed.

Ring size isn’t fixed forever - lots of everyday factors can affect it.

Yes. Fingers are often smaller in winter due to the cold and can swell in warmer summer weather. Your size can even change slightly over the course of a single day.

Weight gain or loss can affect finger size, which means your ring might feel tighter or looser over time.

Definitely. Wider bands fit more snugly than thinner ones, so you may need a slightly larger size for a wide ring.

Ideally, somewhere in between.

  • It should slide over your knuckle without pain
  • It shouldn’t feel so loose that you worry about losing it
  • If you plan to stack or layer the ring with others, a slightly larger size can be more comfortable

Personal preference also plays a part. Some people like a snug fit that doesn’t move, while others prefer a ring they can turn around easily.

In many cases, yes - but not endlessly. Each resize slightly affects the metal, so there are limits depending on the ring’s design and condition. A jeweller can advise whether further resizing is possible.

Unfortunately, once a ring has been resized, it is no longer eligible for return. Resizing is a permanent alteration made specifically to fit you, which means the piece cannot be restored to its original condition or resold. As a result, our standard returns policy no longer applies once this service has been carried out. If you’re unsure about sizing, we always recommend confirming your ring size before proceeding with any adjustments.

Need a Different Size?

Need a Different Size?

Every ring we sell comes with aĀ 30-day free resizing service. If your ring doesn't fit perfectly when it arrives, simply get in touch — no fuss, no charge.

You can also visit us in store for a free in-person sizing appointment with one of our expert jewellers.

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