Carat to Ratti Conversion Chart & Guide

Natural Sri Lankan yellow sapphire (Pukhraj)

Buying guide

At G for Gemstones, 1 ratti ≈ 0.91 carat, so to convert carats to ratti, divide by 0.91.

A 5.00 carat stone is about 5.5 ratti, and a 7.25 ratti stone is about 6.6 carats. Every loose stone we list shows both values.

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1 ratti≈ 0.91 carat

1 carat200 mg

Carats → rattiDivide by 0.91

Common guideline~1 ratti per 10 kg

What is a carat?

The carat (ct) is the international unit for gemstone weight. One metric carat is exactly 200 milligrams (0.2 g). Gem labs, certificates and international buyers always use carats.

What is a ratti?

Ratti is the traditional Indian unit for gemstones, originally based on the weight of a Gunja (rosary pea) seed. Astrologers in India often prescribe stones in ratti. Different traditions use slightly different ratti values, but the common jeweller's ratti, and the one we use, is about 0.91 carat (roughly 182 mg).

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Carat to ratti chart

Carats	Ratti (approx.)
2.00	2.2
3.00	3.3
4.00	4.4
5.00	5.5
6.00	6.6
7.00	7.7
8.00	8.8
9.00	9.9
10.00	11.0
12.00	13.2
15.00	16.5

Ratti to carat chart

Ratti	Carats (approx.)
3	2.73
4	3.64
5	4.55
6	5.46
7	6.37
8	7.28
9	8.19
10	9.10
12	10.92

How to convert yourself

Carats → ratti: carats ÷ 0.91
Ratti → carats: ratti × 0.91
Carats → grams: carats × 0.2

How much should my gemstone weigh?

A widely used traditional guideline is about 1 ratti for every 10 kg of body weight, so a 60 kg adult would wear around 6 ratti (about 5.5 carats). Many astrologers also set minimums for particular stones, for example at least 2–3 carats for blue sapphire. Your astrologer may advise differently based on your chart, so treat these as starting points, not rules.

Why the same stone can show different ratti

Because some sellers use a different ratti value, the same stone may be described with a different ratti number elsewhere. When comparing prices, always compare carats, which are standard worldwide.