Gemstone Carat Weight to Grams, Milligrams, Troy Grains & Round Cut mm Converter

Convert gemstone Carats & Points to grams, milligrams, grains, and diamond mm diameter.

Gemstone Mass & Round Cut Size
0.3 g (300 mg)
1.5 ct (150 pts) = 0.3 g = 4.63 Troy grains
Grams & Milligrams 0.3 g (300 mg)
Jeweler Points (100 pts = 1 ct) 150 points
Troy Grains 4.63 gr
Est. Round Brilliant Diamond Diameter ~7.44 mm
Inputs
carats (ct)
Gemstone weight in metric carats (1 ct = 0.200 grams).
Results & Graph
Gemstone Mass & Round Cut Size
0.3 g (300 mg)
1.5 ct (150 pts) = 0.3 g = 4.63 Troy grains
Grams & Milligrams
0.3 g (300 mg)
Jeweler Points (100 pts = 1 ct)
150 points
Troy Grains
4.63 gr
Est. Round Brilliant Diamond Diameter
~7.44 mm

Gemstone Mass & Round Cut Size Sensitivity & Breakdown

1.5 ct (150 pts) = 0.3 g = 4.63 Troy grains
Graph 1 • Gemstone Weight Carats Sensitivity Recalculates the domain equation across 50% to 150% of the primary input while holding other parameters constant.
0 ~7.44 mm round 0.5 ~7.44 mm round 1.1 ~7.44 mm round 50%: 0.15 ~7.44 mm round 0.1 50% 75%: 0.225 ~7.44 mm round 0.2 75% 100%: 0.3 ~7.44 mm round 0.3 100% 125%: 0.375 ~7.44 mm round 0.4 125% 150%: 0.45 ~7.44 mm round 0.5 150%
Graph 2 • Primary & Supporting Metric Comparison Compares the primary output alongside supporting domain benchmarks.
Gemstone Mass & Round Cut Size 0.3 g (300 mg) Grams & Milligrams 0.3 g (300 mg) Jeweler Points (100 pts = 1 ct) 150 points Troy Grains 4.63 gr
Graph 3 • Exact Output Table & Units Displays each calculated output in its exact domain unit.
Gemstone Mass & Round Cut Size0.3 g (300 mg)Grams & Milligrams0.3 g (300 mg)Jeweler Points (100 pts = 1 ct)150 pointsTroy Grains4.63 grEst. Round Brilliant Diamond Diameter~7.44 mm
Summary: A 1.5-carat (150-point) gemstone weighs exactly 0.3 grams (300 mg) and measures ~7.44 mm across in a standard round brilliant diamond cut.
Summary: A 1.5-carat (150-point) gemstone weighs exactly 0.3 grams (300 mg) and measures ~7.44 mm across in a standard round brilliant diamond cut.
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Interactive chart & math engine powered by CalculatorGraph

Gemstone Mass & Round Cut Size Reference Schedule

Carats (ct)PointsGrams (g)Milligrams (mg)Est. Round Diamond mm
0.25 ct25 pts0.05 g50 mg~4.09 mm
0.5 ct50 pts0.1 g100 mg~5.16 mm
1 ct100 pts0.2 g200 mg~6.5 mm
1.5 ct150 pts0.3 g300 mg~7.44 mm
2 ct200 pts0.4 g400 mg~8.19 mm
3 ct300 pts0.6 g600 mg~9.37 mm

Formula & Mathematical Methodology: Carat ↔ Grams & Diamond mm Formula

Grams = Carats × 0.200
Milligrams = Carats × 200
RoundDiamondmm ≈ 6.50 × Carats1/3
Grams = Carats × 0.200; Milligrams = Carats × 200; RoundDiamond_mm ≈ 6.50 × Carats^(1/3)
  • Gemstone Weight Carats: Gemstone weight in metric carats (1 ct = 0.200 grams).

Rounding: Full IEEE-754 double precision internally; display values formatted to 2–4 significant figures.

Worked Example: Default Carat ↔ Grams & Diamond mm Scenario

Convert metric gemstone Carats (1 ct = 200 mg = 0.200 g) and Points (100 pts = 1 ct) into grams, milligrams, Troy grains, Pearl Momme, and estimated round-brilliant diamond diameter (mm).

  1. Enter parameters for Carat ↔ Grams & Diamond mm in the input controls.
  2. Apply formula: Grams = Carats × 0.200; Milligrams = Carats × 200; RoundDiamond_mm ≈ 6.50 × Carats^(1/3).
  3. Inspect the 3 interactive SVG charts and comparison table for sensitivity across input ranges.
Result: Produces instant Carat ↔ Grams & Diamond mm output with domain-verified units and sensitivity table.

Frequently Asked Questions

How is Carat ↔ Grams & Diamond mm calculated?

Gemstone Carat Weight to Grams, Milligrams, Troy Grains & Round Cut mm Converter uses the verified equation: Grams = Carats × 0.200; Milligrams = Carats × 200; RoundDiamond_mm ≈ 6.50 × Carats^(1/3). Adjust any input field to recalculate all outputs and 3 SVG visualizations in real time.

What units does the Carat ↔ Grams & Diamond mm tool use?

Each field displays its exact unit label (carats (ct)) so results remain dimensionally consistent.

Can I solve backwards for a target output using Goal Seek?

Yes. Click "🎯 Goal Seek" in the results toolbar to solve backwards for any numeric input parameter.

Unit Conversions · Jewelry, Land & Culinary Units

Gemstone Carat Weight to Grams, Milligrams, Troy Grains & Round Cut mm Converter: inputs, method, and how to read the result

Convert gemstone Carats & Points to grams, milligrams, grains, and diamond mm diameter.

Choose inputs for the case you are checking

The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.

  • Gemstone Weight Carats: Gemstone weight in metric carats (1 ct = 0.200 grams).

What the calculation includes

With the default values shown, Gemstone Mass & Round Cut Size is 0.3 g (300 mg). The calculation follows Carat ↔ Grams & Diamond mm Formula; the formula and variable definitions above show how the inputs combine.

One-input check: With the other defaults held constant, changing Gemstone Weight Carats from 1.5 carats (ct) to 1.65 carats (ct) changes Gemstone Mass & Round Cut Size from 0.3 g (300 mg) to 0.33 g (330 mg). This is a comparison inside the calculator's stated model, not a prediction.

Where to use caution

  • Inputs are within standard operating ranges for the specified equation.
  • Extreme boundary conditions may require specialized empirical adjustments.

Scope: Global Standard Check the assumptions and limitations against your situation before relying on the estimate.

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