How much does a 3.00 to 4.99ct J SI1 lab grown round diamond cost?

As of October 2026, 3.00 to 4.99ct J SI1 lab grown round diamonds typically cost £537 GBP to £4,725 GBP, with a median price of £2,106 GBP. There are currently 54 diamonds matching this specification available across retailers.

Where can I find the best price on a J SI1 round diamond?

About 46% of these diamonds are available at multiple retailers, with an average price spread of 62%. A comparison tool like Carat Hunter lets you see all the prices side by side.

3.00 to 4.99ct J SI1 Lab Grown Round

Quick answer

As of October 2026, there are 54 lab grown round diamonds with J colour and SI1 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run £537 GBP to £4,725 GBP, with a median of £2,106 GBP. At least 22 retailers stock this exact specification, and 46% of the stones appear at more than one of them, with an average price spread of 62%. Half of all listings fall between £786 GBP and £1,702 GBP per carat. The same specification in natural form lists at a median of about £7,148 GBP per carat. Over the last 30 days the median price moved -0.2% and the number of listings moved -4.3%.

Three of the best scored stones at this specification right now:

Caratlytics Diamond Price Index, September 2026: natural diamonds at 2,335 USD per carat and lab-grown at 443 USD per carat, a natural to lab ratio of 5.3 to 1. Round lab grown stones in the index: 414 USD per carat, -5.0% month on month. See the full index release

Figures come from current listings across more than 100 retailers and refresh daily. The index is a monthly release.

Last updated: October 2026

Available

Lowest Price

£490 GBP

Highest Price

£53,537 GBP

Average Price

£3,757 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

46.1%

Price Spread

61.5%

30-Day Price Trend

-0.2%

30-Day Supply Change

-4.3%

Volatility (30d)

0.00

Price Range

Price per carat distribution across retailers

$1,984/ct

10th Percentile

$364

Median

$1,984

90th Percentile

$3,174

Score Distribution

115 diamonds scored across 4 quality tiers

Excellent

47 (40.9%)

Very Good

23 (20.0%)

Good

41 (35.7%)

Average

4 (3.5%)

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Related Specifications

D IF D VVS1 D VVS2 D VS1 D VS2 D SI1 E IF E VVS1 E VVS2 E VS1 E VS2 E SI1 F IF F VVS1 F VVS2 F VS1 F VS2 F SI1 G IF G VVS1 G VVS2 G VS1 G VS2 G SI1 H IF H VVS1 H VVS2 H VS1 H VS2 H SI1 I IF I VVS1 I VVS2 I VS1 I VS2 I SI1