Choosing the correct ring size is essential to ensure comfort, longevity, and peace of mind. Whether you’re buying an engagement ring, a wedding band, or a gift, learning how to measure at home saves time, avoids costly resizing, and ensures the perfect fit.
Perfect fit · UK N the ring stops where it sits snug
Why it matters
Getting it right the first time
An incorrectly sized ring may feel uncomfortable, fall off, or be too tight to wear. Measuring correctly from the start avoids disappointment, resizing costs, or even damaging the ring during alterations.
Too loose
Spins, slips — and can fall off.
Perfect fit
Snug, secure, comfortable all day.
Too tight
Pinches, and won’t pass the knuckle.
Measure at home
Three simple ways — no jeweller needed
Keep scrolling. Each method plays out step by step.
Ring sizer
S19.1 mm acrossTOO LOOSE — TRY A SMALLER SIZE
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Use a ring sizer
One of the most accurate methods. A plastic or metal sizing tool lets you test multiple sizes and find the ideal fit quickly.
Get a sizing tool
Plastic or metal. Many online jewellery stores offer affordable ring sizers to use at home.
Test multiple sizes
Try each one on the finger the ring will be worn on.
Find the ideal fit
Snug enough to stay put, easy enough to slide over the knuckle.
Existing ring
0.0 MM
Measure an existing ring
If you already have a ring that fits well, measure its inside diameter with a ruler or caliper, then match it to the sizing chart.
Pick a ring that fits well
Ideally one worn on the same finger.
Measure the inside diameter
Edge to edge across the inside of the band, with a ruler or caliper.
Match it to the chart
Find your diameter in the conversion chart to get your exact size.
String or paper
0.0 MM
Use string or paper
All you need is a strip of paper or string and a ruler.
Wrap
Wrap a strip of paper or string around your finger.
Mark
Mark the point where it overlaps.
Measure
Lay it flat and measure the length with a ruler.
Compare
Check that length against the ring size chart.
Your size
Enter your measurement
Slide to your number, or hold a ring that fits against the screen and slide until the circle matches its inner edge.
53.8mm
UKN
US6 3/4
EU54
A UK N measures 17.1 mm across and 53.75 mm around.
NUK SIZE
Actual size on most screens. Hold your ring here and match the inner edge.
Conversion chart
UK, US & EU sizes
Ring sizes vary globally. Tap a row to load it into the size finder.
UKUSEUDiameterDiam.CircumferenceCirc.
UK sizes follow British Standard BS 6820: each letter adds 1.25 mm of inside circumference, with size C at 40 mm. US sizes add 2.55 mm per whole size and are shown to the nearest quarter. EU sizes are the inside circumference in millimetres.
Tips for accuracy
Four things the experts know
Measure late in the day
Measure your finger at the end of the day for the most accurate size.
Keep hands warm
Cold fingers shrink slightly, so make sure your hands are warm.
Between sizes? Round up
If you’re between sizes, always round up for comfort.
Wide bands fit smaller
Wider rings may require a slightly larger size than thinner bands.
Buying as a gift?
Discreetly borrow one of their existing rings to measure.
If that’s not possible, our customer service team can help you estimate the most suitable size.
Still unsure?
Our jewellery experts are happy to help you find the perfect fit.
Follow this guide and you can confidently measure your ring size at home, avoid resizing issues, and ensure a perfect fit every time. For more on buying rings, visit our jewellery knowledge centre.
Yes, using our ring size guide, string, paper, or an existing ring.
Many rings can be resized, but always check before purchase. Our team can guide you.
No. Use our conversion chart to switch between UK, US, and EU ring sizes.
