How much does a 1.00 to 1.49ct J SI1 lab grown round diamond cost?

As of October 2026, 1.00 to 1.49ct J SI1 lab grown round diamonds typically cost £463 GBP to £3,060 GBP, with a median price of £797 GBP. There are currently 36 diamonds matching this specification available across retailers.

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

About 28% of these diamonds are available at multiple retailers, with an average price spread of 86%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.00 to 1.49ct J SI1 Lab Grown Round

Quick answer

As of October 2026, there are 36 lab grown round diamonds with J colour and SI1 clarity in the 1.00 to 1.49ct range available across retailers worldwide. Prices typically run £463 GBP to £3,060 GBP, with a median of £797 GBP. At least 30 retailers stock this exact specification, and 28% of the stones appear at more than one of them, with an average price spread of 86%. Half of all listings fall between £588 GBP and £1,381 GBP per carat. The same specification in natural form lists at a median of about £1,707 GBP per carat. Over the last 30 days the median price moved -22.6% and the number of listings moved -56.3%.

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

£137 GBP

Highest Price

£4,148 GBP

Average Price

£1,095 GBP

Market Intelligence

Retailers Selling

Cross Retailer %

27.9%

Price Spread

86.5%

30-Day Price Trend

-22.6%

30-Day Supply Change

-56.3%

Volatility (30d)

0.08

Price Range

Price per carat distribution across retailers

$1,221/ct

10th Percentile

$501

Median

$1,221

90th Percentile

$2,918

Score Distribution

107 diamonds scored across 4 quality tiers

Excellent

27 (25.2%)

Very Good

7 (6.5%)

Good

25 (23.4%)

Average

48 (44.9%)

Find Your Diamond

Search 36 J SI1 round diamonds and compare prices.

Search Diamonds

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