Diamond shopping runs on carats — the 1-carat solitaire, the 2-carat upgrade — but the carat is a mass unit with a fabulously analog origin: traders once weighed gems against carob seeds, which are remarkably uniform in weight. The modern metric carat, standardized in 1907, is exactly 0.2 grams, or 200 milligrams. Type 1.5 into the Carats (ct) box and the Grams (g) readout shows 0.3, with 300 milligrams and about 0.0106 ounces in the bonus boxes. That precision matters because diamond prices scale brutally with carat weight — a 2-carat stone costs far more than twice a 1-carat stone — and jewelers weigh to the hundredth of a carat. Gold buyers meet the same word with a totally different meaning: gold "karat" (with a K) measures purity, not weight, so 24-karat gold is pure gold. Whether you are comparing loose stones online, checking a jeweler's scale, or converting a gemstone certificate, multiplying carats by 0.2 gives you grams every time.

With the pre-filled defaults — Carats (ct) 1 — the Carat to Gram returns Grams (g) 0.2000, Milligrams (mg) 200.00, Ounces (oz) 0.007055. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.