Diamond Carat Calculator
Calculate diamond weight in carats based on shape and dimensions
Calculate Diamond Carat Weight
For round diamonds, depth is typically 60% of diameter
Advanced Settings (Optional)
Typically 1-3% for round diamonds
Accounts for irregular shapes and cutting variations
Diamond Weight Results
Formula used: Diameter² × Depth × 0.0061 × (1 + GT)
Shape: Round
Diamond Size Category
Example Calculation
Round Diamond Example
Shape: Round Brilliant
Diameter: 6.5 mm
Depth: 4.0 mm (60% of diameter)
Girdle Thickness: 2%
Calculation
Weight = 6.5² × 4.0 × 0.0061 × (1 + 0.02)
Weight = 42.25 × 4.0 × 0.0061 × 1.02
Weight = 1.05 carats
Popular Diamond Shapes
Carat Weight Guide
Understanding Diamond Carat Weight Calculation
What is Diamond Carat Weight?
Carat weight is one of the 4 Cs of diamond grading (Cut, Color, Clarity, Carat). It measures the physical weight of the diamond, with one carat equal to 200 milligrams or 0.2 grams. Carat weight is a primary factor in determining a diamond's value.
Why Calculate from Dimensions?
- •Estimate weight when precise scale isn't available
- •Verify diamond specifications when purchasing
- •Compare different diamond shapes and sizes
- •Quality control in diamond cutting
Key Factors in Calculation
Girdle Thickness (GT)
The thin band around the diamond's widest part. Affects total weight calculation and is typically 1-3% of the diamond's diameter.
Weight Correction (WC)
Accounts for irregularities in cutting and non-standard proportions that can affect the final weight calculation.
Adjustment Factor (AF)
Shape-specific factor that varies based on length-to-width ratio for fancy shapes like emerald, marquise, pear, and radiant cuts.
Important Notes
- • These calculations provide estimates. Professional certification requires precise measurement equipment.
- • All dimensions must be in millimeters for accurate calculations.
- • Results can vary ±5-10% from actual weight due to cutting variations and measurement precision.
- • For insurance or appraisal purposes, always use certified measurements from reputable gemological laboratories.