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

As of October 2026, 1.00 to 1.49ct I SI1 lab grown round diamonds typically cost €476 EUR to €1,815 EUR, with a median price of €1,034 EUR. There are currently 140 diamonds matching this specification available across retailers.

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

About 37% of these diamonds are available at multiple retailers, with an average price spread of 101%. A comparison tool like Carat Hunter lets you see all the prices side by side.

1.00 to 1.49ct I SI1 Lab Grown Round

Quick answer

As of October 2026, there are 140 lab grown round diamonds with I colour and SI1 clarity in the 1.00 to 1.49ct range available across retailers worldwide. Prices typically run €476 EUR to €1,815 EUR, with a median of €1,034 EUR. At least 29 retailers stock this exact specification, and 37% of the stones appear at more than one of them, with an average price spread of 101%. Half of all listings fall between €810 EUR and €1,989 EUR per carat. The same specification in natural form lists at a median of about €2,833 EUR per carat. Over the last 30 days the median price moved -24.2% and the number of listings moved -14.0%.

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

140

Lowest Price

€118 EUR

Highest Price

€5,426 EUR

Average Price

€1,206 EUR

Market Intelligence

Retailers Selling

Cross Retailer %

36.6%

Price Spread

101.4%

30-Day Price Trend

-24.2%

30-Day Supply Change

-14.0%

Volatility (30d)

0.06

Price Range

Price per carat distribution across retailers

$1,293/ct

10th Percentile

$417

Median

$1,293

90th Percentile

$2,903

Score Distribution

293 diamonds scored across 4 quality tiers

Excellent

115 (39.2%)

Very Good

14 (4.8%)

Good

101 (34.5%)

Average

63 (21.5%)

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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