Silicone Ring Size Guide: How to Get the Perfect Fit

Written by Alan MacLachlan, Owner, Newman Bands (Horsham, West Sussex)

Alan has overseen more than 100,000 ring orders since founding Newman Bands with Clare. Newman Bands is the trading name of Manzora Ltd, incorporated in 2001; it has sold men's rings since 2019, with every design and size held in stock in the UK and same-day dispatch on orders before 5pm — most orders arrive within one to two days. Alan personally answers customer queries on metal selection and ring choice every week. Newman Bands has more than 15,000 verified customer reviews — rated 4.99 out of 5 on Reviews.io and 5.0 on Trustpilot.

Silicone rings size differently from metal rings — and if you order based on your tungsten or titanium ring size without accounting for this, you’ll end up with a ring that’s either too loose or unnecessarily tight. This guide explains how silicone sizing works, how to measure at home, and what to do if your ring doesn’t fit first time.

The key fact: silicone rings have a small amount of stretch. Most wearers find that taking the smaller of our two nearest sizes from their metal ring size gives the best fit. Measure with a strip of paper or use our free ring sizer, and if you’re between sizes, go smaller.

Why Silicone Ring Sizing Differs from Metal Ring Sizing

A metal ring — whether tungsten, titanium, or gold — is a rigid structure. It does not flex. When you choose a metal ring size, you need a ring that clears your knuckle and sits comfortably on the base of your finger with no extra give.

Silicone is different. It has elasticity — a Our silicone is a soft, flexible medical-grade compound. A silicone ring that feels snug at rest will stretch to clear your knuckle and compress back to a comfortable fit once it is seated.

This means your metal ring size and your silicone ring size are not the same. Most wearers find that sizing down half a UK size gives the ideal silicone fit — snug enough to stay in place, flexible enough to remove comfortably.

Do not order silicone using your metal ring size directly. The majority of silicone ring sizing problems we see at Newman Bands come from customers ordering the same size as their tungsten or gold ring without accounting for stretch. Size down 0.5 as a starting point.

“Gorgeous ring, bought as a 60th birthday gift. The 1st ring was too big, it was returned a smaller ring sent within a couple of days. Fantastic service. Getting married soon, so I’ll be back to buy his wedding ring.”

Joanne Houghton, Holyhead

verified customer review — quoted word-for-word

How to Measure Your Silicone Ring Size at Home

You can get an accurate silicone ring size at home with nothing more than a strip of paper and a ruler. Measure at the end of the day, when your fingers are at their largest — fingers swell slightly during the day and in warmer weather.

Method 1 — Paper strip (recommended for most people): Cut a strip of paper approximately 10mm wide and 100mm long. Wrap it snugly around the base of the finger you intend to wear the ring on. Mark where the strip overlaps itself with a pen. Measure the length from the end to the mark — this is your finger circumference in millimetres. Find your UK letter size in the table below.

Method 2 — Existing ring: If you have a ring that already fits the intended finger, measure its internal diameter in millimetres with a ruler. Place it flat on a white surface and measure across the inside of the band. Use the diameter column in the table below to find your UK size.

Method 3 — Free ring sizer from Newman Bands: If you are unsure of your size, select the ring you want to order and choose “I don’t know my ring size” from the dropdown at checkout. We’ll send you a free ring sizer. Once you know your size, order the ring. The whole process from requesting the sizer to receiving your ring can be completed in as little as three days.

UK size (the only sizes we stock)	US size	Finger circumference (mm)	Ring diameter (mm)
M	6	51.9	16.5
O	7	54.4	17.3
Q	8	57.0	18.1
S	9	59.5	18.9
U	10	62.1	19.8
W	11	64.6	20.6
Y	12	67.2	21.4
Z1	13	69.7	22.2
Z3	14	72.3	23.0

Our silicone rings are made in whole US sizes only — US 6 to 14, which is why the UK letters step two at a time and why there is no half size. If you measure between two of ours, take the smaller one. Full range and conversions: our UK ring size chart.

Note: the sizes listed above show the most commonly ordered silicone sizes at Newman Bands. If your size is not shown, contact us — we can advise on stock availability for intermediate sizes.

Tip: UK ring sizes use letters, not numbers. If you are used to US sizing (numerical, 1 through 16), find your circumference or diameter measurement and match it to the UK letter — do not try to convert numerically.

Should a Silicone Ring Be Tight or Loose?

A well-fitted silicone ring should feel snug — not tight. The “three-second knuckle test” is the simplest way to check: put the ring on and take it off three times. It should slide over the knuckle with slight resistance, then sit comfortably on the base of the finger with no deep red indentations. It should not spin freely when your hands are cold or wet.

Too tight: If the ring leaves a lasting red mark on the skin after 15 minutes of wear, or feels uncomfortable when your hands are warm, it is too small. Size up by half a UK size.

Too loose: If the ring spins freely on your finger when your hands are cool or wet, or slips towards your knuckle during normal movement, it is too large. Size down by half a UK size.

Finger swelling: Fingers swell in hot weather, after exercise, and during pregnancy. If you wear your ring in high-sweat environments, consider sizing true to your metal ring size rather than down 0.5 — the extra stretch will accommodate swelling without discomfort.

The Silicone Sizing Rule: Start at the smaller of our two nearest sizes from your metal ring size. If you are between two sizes, go smaller. Silicone will stretch to fit; it will not compress to feel comfortable if it is too big.

Silicone Ring Size by Activity and Use Case

Use Case	Sizing Recommendation	Reason
Everyday wear	True to size	Comfort balance for all-day wear
Gym / CrossFit	True to size	Sweat and grip increase ring movement; true size stays put
Healthcare / Nursing	True to size	Frequent hand washing; ring should not spin or slip
Sleeping	take the smaller size	Hands often swell slightly during sleep; snugger fit prevents slipping off
Hot climate / outdoor	True to size or 0.5 up if significant swelling expected	Heat causes finger expansion; allow for this

“Perfect item. Arrived so quickly and exactly as described/advertised. Bought the silicone ring (plus an extra pack of 3 as it was a bargain!) for my husband to wear at work/in the gym etc. Looks so good on and great quality. So happy with it, would definitely recommend!”

Brianna Trevis, Steyning

verified customer review — quoted word-for-word

What to Do If Your Silicone Ring Doesn't Fit

All Newman Bands silicone ring orders are covered by our 100-day return policy. Silicone rings cannot be engraved, so every silicone order qualifies as a non-personalised item and is eligible for a full return within 100 days — and size exchanges are free and unlimited.

If your ring is too tight, return it and exchange for the next half size up. If it is too loose, size down. Newman Bands will process your exchange promptly.

If your ring size varies significantly between your dominant and non-dominant hand, or between different fingers, measure the specific finger you plan to wear the ring on — not the finger you usually measure from. Ring size varies considerably between fingers on the same hand.

Sizing for Gifts: If you are ordering a silicone ring as a gift and are unsure of the recipient’s ring size, consider ordering a ring sizer first. Select the ring, choose “I don’t know my ring size” from the dropdown, and we’ll send a free sizer. The process takes three days and prevents the disappointment of an ill-fitting gift.

For general ring sizing guidance covering tungsten and titanium as well as silicone, see our UK ring size chart — including a complete UK ring size chart from J to Z4 and sizing rules by ring type.

Frequently Asked Questions

Do silicone rings come in half sizes?

Newman Bands silicone rings are available in alternate UK letter sizes (M, O, Q, S, U, W, Y, Z1, Z3) — there are no half sizes. Because silicone stretches 10 to 15 per cent, the flexible nature of the material means that a standard size will fit a range of finger circumferences. If you are between whole sizes, go to the next size down rather than up — the stretch will accommodate the difference.

Can I wear a silicone ring if I have a latex allergy?

Yes. Newman Bands silicone rings are made from medical-grade silicone and contain no latex. Silicone and latex are chemically unrelated materials — a latex allergy does not indicate any risk from silicone. Silicone is also free from nickel, cobalt, and BPA.

Will a silicone ring stretch out and become too big?

Over many years of daily wear, the elasticity of a silicone ring can reduce slightly. A ring that has permanently lost its shape — meaning it no longer returns to its original size and profile after being removed — should be replaced. This is a natural end-of-life indicator rather than a defect. At £18, replacement is straightforward.

Is sizing different for women's and men's silicone rings?

The same UK ring size system applies to all Newman Bands silicone rings. Women’s ring fingers are typically smaller than men’s — common women’s sizes are J to P (approximately 16.4–18.6mm diameter), while men’s sizes tend to fall in the N to T range (17.9–20.2mm diameter). Measure the specific finger regardless of gender assumptions.