Round Cut Split Shank Lab Grown Diamond Engagement Ring (1–5 ct, 14K/18K/Platinum)

Round Cut Split Shank Lab Grown Diamond Engagement Ring (1–5 ct, 14K/18K/Platinum)

Q: What is a UK size L in US sizing?

A UK L and a half is a US 6, the most common women's size, with an inside diameter of 16.5 mm. A plain UK L sits just below that, between a US 5.5 and a US 6.

Q: What does a European ring size number mean?

Under ISO 8653 the European size is the inside circumference of the band in millimeters. A European 52 is a ring measuring 52 mm around the inside, which corresponds to a US 6.

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Diamond Quality - F-G / VS1-VS2

$1,049.00

Shape

Round

Carat ( Center Stone)

Quantity

1
2
3
4
5
6
7
8
9
10 +

Quantity

Ring size

Not sure of your size? , or contact us and we’ll help.

Service plan

Find your ring size

1 Calibrate your screen

Hold any bank or ID card against the screen, long side along the bar. Drag the slider until the bar is exactly as long as the card. You only do this once.

Card length

Inside measurements of the band. Tap a size to choose it.

US size	Inside diameter	Circumference

UK, European and Japanese conversions

A Measure a ring that fits

Lay it flat and measure straight across the inside edge at its widest point, in millimeters. Find it in the size chart.

B Use a strip of paper

Cut a strip about 5 mm wide, wrap it snugly around the base of the finger, mark the overlap and measure to the mark. That is the circumference. Don't use string, it stretches.

Tips: measure at the end of the day when hands are warm; between two sizes, choose the larger; keeping it a surprise, borrow a ring she wears on that finger.

Not sure about your size?

Call (888) 709-7077 Book a free video consultation

Free insured shipping, both ways
Lifetime warranty on every piece
Certificate of authentication included
30 days to change your mind

Questions before you buy? Call (888) 709-7077 or book a free consultation.

Product Details

A timeless symbol of love, reimagined. The split shank band on this round-cut engagement ring creates a graceful flow toward a brilliant solitaire — adding the illusion of extra sparkle and a slimmer, more elegant finger silhouette.

The Center Stone

A round brilliant lab-grown diamond, hand-selected for near-colorless grade and VS2+ clarity — the same optical brilliance as a natural diamond, at a fraction of the cost. Available in 1, 2, 3, 4, and 5 carat options.

The Setting

The split shank band tapers from the wearer's finger and rejoins beneath the center stone, lifting it visually and protecting it structurally. A modern silhouette on a classic foundation.

Choose Your Metal

Available in 14K White, Yellow, or Rose Gold; 18K White, Yellow, or Rose Gold; or solid Platinum. Each ring is hand-finished to order.

Why Lab-Grown?

Our diamonds are chemically and optically identical to mined diamonds — but they're created without environmental disruption or ethical concerns. You get more carat, better clarity, and a clear conscience.

Included with Every Ring

Certificate of authenticity
Complimentary ring sizing
Free insured shipping

Need a custom size or carat weight not listed? Contact us — every ring is made to order.

Feeling Unsure About Your Purchase?

Book a Free Jewelry Consultation Call with Our Experts and Get Personalized Guidance to Help You Choose the Perfect Piece!

Stone Type

All our jewelry features lab-grown diamond stones, offering the same brilliance and beauty as natural diamonds with a commitment to sustainability and ethical sourcing.

IGI-Certified Diamonds

Our lab-grown diamonds of 1 carat and larger come with an independent IGI grading report, so you know exactly what you are getting. Every piece, whatever its size, is made to order and checked by our jewelers in our workshop on 48th Street before it ships.

Free Shipping in the USA

Enjoy complimentary shipping on all orders within the United States, ensuring your jewelry arrives safely and promptly. For more information, visit our Free Shipping page.

Need help with sizing?

Contact our support team via chat, email at info@diamonddomain.com, or call us at 888-709-7077

Ring sizing systems differ by country, but they all describe the same physical thing: the inside circumference of the band in millimeters. Convert by finding your millimeter measurement, not by converting number to number — that is where mistakes creep in.

We size in US measurements. If you have a size from another system, use the chart below to find its US equivalent before ordering.

Conversion chart

Ring size conversion across the four main systems
US / Canada	UK / Australia	Europe (ISO)	Japan / China	Diameter (mm)	Circumference (mm)
3	F	44	4	14.1	44.2
3.5	G	45½	5	14.5	45.5
4	H	47	7	14.9	46.8
4.5	I	48	8	15.3	48.0
5	J½	49½	9	15.7	49.3
5.5	K½	50½	10	16.1	50.6
6	L½	52	11	16.5	51.9
6.5	M½	53	13	16.9	53.1
7	N½	54½	14	17.3	54.4
7.5	O½	55½	15	17.7	55.7
8	P½	57	16	18.1	57.0
8.5	Q½	58	17	18.5	58.3
9	R½	59½	18	19.0	59.5
9.5	S½	61	19	19.4	60.8
10	T½	62	20	19.8	62.1
10.5	U½	63½	22	20.2	63.4
11	V½	64½	23	20.6	64.6
11.5	W½	66	24	21.0	65.9
12	X½	67	25	21.4	67.2
12.5	Y½	68½	26	21.8	68.5
13	Z½	70	27	22.2	69.7

How each system works

US and Canada use a numeric scale in half-size steps. Each full size is roughly 0.4 mm of diameter, or about 1.3 mm of circumference.
UK, Ireland, Australia and New Zealand use letters, with half sizes marked by a ½. The alphabet runs from A upward, so a UK L½ is a US 6.
Europe (ISO 8653) is the most literal: the number is the inside circumference in millimeters, rounded. A European 52 is a band 52 mm around.
Japan and China use their own numeric scale, which does not map evenly onto the others. Treat these as the closest match rather than an exact equivalent, and confirm against the millimeter columns.

Convert by millimeters, not by number

Systems round differently, and rounding twice compounds the error. If you know your size in one system, read across to the millimeter columns first, then find the nearest US size to that measurement. Where a measurement falls between two sizes, go up rather than down — a loose ring can be taken in, a ring that will not clear the knuckle cannot be worn.

Do not have a size in any system? Measure it at home in about five minutes.

Frequently asked questions

What is a UK size L in US sizing?

A UK L½ is a US 6, the most common women's size, with an inside diameter of 16.5 mm. A plain UK L sits just below that, between a US 5.5 and a US 6.

What does a European ring size number mean?

Under ISO 8653, the European size is the inside circumference of the band in millimeters. A European 52 is a ring measuring 52 mm around the inside, which corresponds to a US 6.

Are Japanese ring sizes the same as US sizes?

No. Japan uses a separate numeric scale that does not increase in step with the US one — a Japanese 11 is a US 6, but a Japanese 20 is a US 10. Always confirm against the millimeter measurement rather than assuming the numbers align.

How much bigger is a half size?

About 0.2 mm of inside diameter, or roughly 0.65 mm of circumference. It is a small difference on paper and a noticeable one on the finger.

Which sizes do you make?

Every ring is made in US half sizes from 3 to 13. Sizes outside that range are available on request — call (888) 709-7077.

Where to go next

Round Cut Split Shank Lab Grown Diamond Engagement Ring (1–5 ct, 14K/18K/Platinum)

$1,049.00

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Round Cut Split Shank Lab Grown Diamond Engagement Ring (1–5 ct, 14K/18K/Platinum)

Diamond Quality - F-G / VS1-VS2

The Center Stone

The Setting

Choose Your Metal

Why Lab-Grown?

Included with Every Ring

Need help with sizing?

Round Cut Split Shank Lab Grown Diamond Engagement Ring (1–5 ct, 14K/18K/Platinum)

Customer Reviews

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