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Ring Sizer

★★★★★ 4.9 from 3,500+ reviews · Loved by 20,000+ customers worldwide

Ring Sizer

Name: Ring Sizer
Brand: Rainbow Rocks Jewellery
Price: 2.0 GBP
Availability: InStock

£2.00

Sale Sold out

Tax included.

Ring size guide

We make full US sizes. The bold letter is the exact UK match; the others fit best in that ring. The mm measurement is the true guide — between two sizes, round up.

US	UK (best fit)	EU / circ.	Diameter
3	E, E½, F, F½	44.0 mm	14.0 mm
4	G, G½, H, H½	47.0 mm	15.0 mm
5	I, I½, J, J½	49.0 mm	15.6 mm
6	K, K½, L, L½	51.75 mm	16.5 mm
7	M, M½, N, N½	54.2 mm	17.25 mm
8	O, O½, P, P½	57.0 mm	18.1 mm
9	Q, Q½, R, R½	59.0 mm	18.8 mm
10	S, S½, T, T½	62.0 mm	19.7 mm

Half or quarter US size? A .25 takes the size below (6.25 → 6); a .5 or .75 rounds up (6.5 or 6.75 → 7).

Measure at home

Wrap paper or string around the base of your finger (not over the knuckle).
Mark the overlap and measure the length in mm.
Match it to the EU / circumference column. Or measure the inside of a ring you own and use the Diameter column.

Tip: measure at the end of the day, when fingers are largest. Between sizes? Size up.

Necklace lengths

We offer 45 cm (18 in) and 50 cm (20 in). Here's where each sits.

Length	Inches	Where it sits
40 cm	16 in	Choker — base of the neck
45 cm	18 in	Most popular — on the collarbone
50 cm	20 in	Just below the collarbone — easy to layer
55 cm	22 in	Upper chest

How to measure

Drape a string around your neck where you'd like the necklace to sit.
Mark the spot and measure against a ruler.
Layering? Choose lengths about 5 cm (2 in) apart.

Bracelet sizes

Measure your wrist, then add about 1.5–2 cm for a comfortable fit.

Wrist measurement	Fit
14–15 cm	Petite
15–16.5 cm	Small / Average
16.5–18 cm	Medium
18–19.5 cm	Large

How to measure your wrist

Wrap paper or string around your wrist, just below the wrist bone.
Mark the overlap and measure in cm.
Add 1.5–2 cm for comfort.

Beaded styles suit most wrists; tennis bracelets are a set length — see the product details.

Still unsure? Message us with your measurement and we'll recommend your size. Every piece has a 365-day guarantee.

Enjoy 15% off your order · code SUMMER15

Free UK delivery over £65 · Worldwide over £95

Ships in 1 day · tracked worldwide from the UK

365-day warranty · we repair or replace, no quibbles

Easy returns · 30 days, no questions asked

Gift-ready packaging · branded box included

Description

Re-usable plastic ring sizer. Easy to use ring measurement tool to get an accurate measurement of your ring size.

Material

Gemstone

Measurements

Size Guide

Everything you need to find the perfect fit. Our pieces are 925 sterling silver finished in 14k gold vermeil, rose gold vermeil or rhodium — and we always tell you exactly what you're buying. If you're ever unsure, message us and we'll happily help.

Rings

Ring size conversion

Every brand sizes a little differently, so we measured our own rings. We make full US sizes, and the chart below maps each one to UK and EU sizes. The bold letter is the exact UK match; the others in that row are the in-between sizes that fit best in that ring.

US	UK (best fit)	EU / circumference	Inner diameter
3	E, E½, F, F½ (or smaller)	44.0 mm	14.0 mm
4	G, G½, H, H½	47.0 mm	15.0 mm
5	I, I½, J, J½	49.0 mm	15.6 mm
6	K, K½, L, L½	51.75 mm	16.5 mm
7	M, M½, N, N½	54.2 mm	17.25 mm
8	O, O½, P, P½	57.0 mm	18.1 mm
9	Q, Q½, R, R½	59.0 mm	18.8 mm
10	S, S½, T, T½ (or larger)	62.0 mm	19.7 mm

The millimetre measurement is the true guide — US, UK and EU are just labels that approximate it. Between two sizes? Round up.

Half & quarter US sizes: We make full US sizes only. If your size ends in .25, choose the full size below (e.g. US 6.25 → size 6) — it sits a touch snug, which is comfortable and secure. If it ends in .5 or .75, round up to the next full size (e.g. US 6.5 or 6.75 → size 7), so it's never too tight.

Measure with string or paper

Wrap a strip of paper or string snugly around the base of your finger — not over the knuckle.
Mark where it overlaps.
Lay it flat against a ruler and measure the length in mm.
Match that number to the EU / circumference column above.

Measure a ring you own

Take a ring that already fits the right finger well.
Measure straight across the inside, in mm.
Match it to the Inner diameter column above.

Fit tips: Measure at the end of the day, when fingers are warmest and largest (cold fingers read up to half a size small). Size over the knuckle if yours are larger. Wider bands fit tighter — size up for chunky styles. Between sizes? Always size up.

Necklaces

Necklace lengths

We currently offer our necklaces in 45 cm (18 in) and 50 cm (20 in). Here's where each length sits, so you can picture it before you choose.

Length	Inches	Where it sits
40 cm	16 in	Choker — sits at the base of the neck
45 cm	18 in	Our most popular — rests on the collarbone
50 cm	20 in	Sits just below the collarbone — easy to layer
55 cm	22 in	Falls on the upper chest

Bold lengths are the sizes we offer. 16 in and 22 in are shown for reference.

How to measure

Take a piece of string and drape it around your neck where you'd like the necklace to sit.
Mark the spot and measure the length against a ruler.
Compare to the chart above. Layering two pieces? Choose lengths about 5 cm (2 in) apart so they sit nicely.

Tip: 45 cm (18 in) suits almost everyone and is the classic everyday length. Go 50 cm (20 in) if you prefer a little more drop or plan to layer.

Bracelets

Bracelet sizes

The right bracelet fit leaves a little room to move comfortably. Measure your wrist first, then check the guide below.

How to measure your wrist

Wrap a strip of paper or string around your wrist, just below the wrist bone (where a bracelet naturally sits).
Mark where it overlaps and measure in cm — that's your wrist size.
For a comfortable fit, add about 1.5–2 cm to your wrist measurement.

Wrist measurement	Fit
14–15 cm	Petite
15–16.5 cm	Small / Average
16.5–18 cm	Medium
18–19.5 cm	Large

Good to know: Our beaded gemstone bracelets are made to suit most wrists, and our tennis bracelets are a set length. Each product page lists the exact length or fit — check there, and if you're between sizes or want it adjusted, just message us.

Still unsure? We'd genuinely rather help you get it right than have you guess — message us with your measurement and we'll recommend your size. Every piece is covered by our 365-day guarantee and a 14-day return window.

Delivery & Returns

Free UK Delivery: Spend over £65 for complimentary standard delivery, or over £95 for free express.

Free Global Shipping: Spend over £95 for free tracked worldwide shipping — including duties covered for all US orders, no surprise fees.

Fast Dispatch: Orders dispatched within 1 working day.

Easy Returns: Return unworn items within 14 days of delivery. Excludes earrings, personalised pieces and custom solid gold items.

365-Day Warranty

We stand behind the quality of every piece. If your jewellery develops a manufacturing fault within 365 days, we'll repair or replace it — no quibbles. Just email us or message us via online chat.

Designed for everyday wear and crafted with care.

See it in motion

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Lab-Grown or Natural Gemstones

Identical composition to mined stones — chosen for beauty and ethics.

14k Gold Vermeil

Thick gold over solid 925 silver — not standard plating.

Gift-Ready Packaging

Arrives beautifully packaged — perfect for meaningful gifting.

True-to-Size Fit

Based on standard US sizing. Between sizes? We recommend sizing up.

Tracked & Secure Delivery

Worldwide shipping with full tracking. USA orders shipped duty paid - no surprise fees.

Made to Last

Secure settings designed for everyday wear.

Loved by customers worldwide

Trusted by 19,000+ customers, with a 4.9/5 rating from over 3,400 reviews.

STUNNING!!

“STUNNING!! Pros: 1. Arrived on time! 2. Much care to pack and ship 3. Well made, looks amazing! Cons: 1. NONE I'm wearing to the symphony next wknd, fave little black dress and these beautiful emeralds! Very happy....”

— Tara E, verified customer

Even prettier in person

“Beautiful ring and even prettier in person. I’m really happy with it!”

— Erin, verified customer

The sparkle is unmatched!

“These earrings are SO pretty and the sparkle is unmatched! I can’t wait to wear them for my wedding!”

“These earrings are SO pretty and the sparkle is unmatched! I can’t wait to wear them for my wedding!”

— Laura, verified customer

Starlight Birthstone Star Ring - Rainbow Rocks Jewellery

About Rainbow Rocks

Jewellery has always been personal to me — it marks our moments, memories, and meaning. I created Rainbow Rocks so beautiful gemstone pieces wouldn't be out of reach: genuine lab-grown and natural gemstones, set in 14k gold vermeil over sterling silver, made for everyday wear. Each piece is made to be worn, loved, and to hold a story of its own.
— Yan, Founder

4.9 Rating from 3,500+ Reviews

Loved by 20,000+ customers worldwide
Lab-Grown & Natural Gemstones

Same composition as mined stones — ethically crafted.
14k Gold Vermeil & Sterling Silver

Thick gold over solid 925 silver — made for everyday wear
365-day guarantee

Every piece covered for a full year — shop with confidence.

Ring Sizer

Why You’ll Love It

Lab-Grown or Natural Gemstones

14k Gold Vermeil

Gift-Ready Packaging

True-to-Size Fit

Tracked & Secure Delivery