Work out diamond carat price instantly with clear inputs, formula shown and shareable results.
Price is carat weight times a per-carat rate adjusted by a quality premium; a carat is exactly 200 milligrams, or 100 points. Per-carat prices jump at round weights, so a 0.99 carat stone can cost noticeably less than a 1.01 carat one of identical quality.
Price
total = carats x base price per carat x (1 + quality premium)
Weight conversion
1 carat = 200 mg = 100 points
total = carats x base price per carat x (1 + quality premium). Price is carat weight times a per-carat rate adjusted by a quality premium; a carat is exactly 200 milligrams, or 100 points.
Per-carat prices jump at round weights, so a 0.99 carat stone can cost noticeably less than a 1.01 carat one of identical quality.
Enter carat weight, base price per carat, cut, colour and clarity premium. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.