Diamond Price Estimate Calculator
Get a rough diamond price from the 4Cs — carat, cut, colour and clarity — by scaling a base price per carat with quality multipliers.
How it works
Price = base/ct × cut × colour × clarity × size premium × carat · size premium ≈ √carat above 1 ct
Diamond pricing follows the 4Cs. Carat drives price non-linearly — a 2 ct stone costs far more than two 1 ct stones because large rough is rarer — which the square-root size premium approximates. Cut, colour and clarity each apply a discount to a top-grade base rate. This is a rough model: real trade pricing uses detailed rate matrices (like the Rapaport list) plus fluorescence, shape and certification, so use this to sanity-check a quote, not to appraise a stone.
Worked example
A 1 ct Excellent / G / VS diamond at a $5,000/ct base: cut 1.0 × colour 0.90 × clarity 0.82 = 0.738 multiplier. Price per carat ≈ $3,690, so the stone is about $3,690.
Frequently asked questions
Why does a 2-carat cost more than double a 1-carat?
Larger gem-quality rough is disproportionately rare, so price per carat climbs with size. Two 1 ct stones are much cheaper than one 2 ct stone of equal quality.
Which of the 4Cs matters most for value?
Carat has the biggest effect on total price, but cut most affects how brilliant a stone looks. Many buyers prioritise an excellent cut and accept a slightly lower colour or clarity grade.
Is this an appraisal?
No. It is an educational estimate. A real valuation needs a graded certificate and current trade rates for that exact shape and grade combination.
Related calculators
Rough educational estimate only — not a professional appraisal.