Carat Weight Calculator

Calculate diamond carat weight from dimensions and convert to other units

Calculate Diamond Carat Weight

Round diamonds comprise about 75% of all diamonds sold

Optional Adjustments

Range: -5% to +18%

Estimated Diamond Weight

0.000
Carats
0.000
Grams
0.00000
Ounces
0.0000
Pennyweights

Quick Examples

1 Carat Round Diamond

Diameter: ~6.5 mm

Depth: ~4.0 mm

Weight: 1.00 ct (0.2 g)

0.5 Carat Princess

Length: ~4.4 mm

Width: ~4.4 mm

Depth: ~3.2 mm

Weight: 0.50 ct (0.1 g)

2 Carat Oval

Length: ~9.0 mm

Width: ~6.5 mm

Depth: ~4.2 mm

Weight: 2.00 ct (0.4 g)

Diamond 4Cs

C

Carat

Weight measurement

1 carat = 0.2 grams

C

Cut

Quality of proportions

Affects brilliance & fire

C

Color

Absence of color

D (colorless) to Z (yellow)

C

Clarity

Absence of inclusions

FL (flawless) to I3 (included)

Quick Tips

1 carat = 0.2 grams = 200 milligrams

Round diamonds are most popular (75% of sales)

Fancy shapes often cost less per carat

Measurements should be accurate to 0.01mm

Understanding Diamond Carat Weight

What is Carat Weight?

Carat weight is one of the famous 4Cs used to evaluate diamonds. One carat equals 0.2 grams or 200 milligrams. The term "carat" comes from the ancient practice of using carob seeds as counterweights on balance scales.

How is it Calculated?

  • Based on diamond dimensions and shape-specific formulas
  • Accounts for shape density differences
  • Considers girdle thickness and cutting irregularities
  • More accurate than visual estimation

Diamond Shape Factors

Round:D² × Depth × 0.0037
Princess:L × W × D × 0.0036
Oval:L × W × D × 0.0037
Emerald:L × W × D × 0.0034

Important Notes

• Girdle thickness affects final weight (0.5% - 7%)

• Correction factors account for cutting irregularities

• Professional appraisal recommended for valuable stones

• Calculator provides estimates, not certified weights