Gemstone Ratti Calculator
Convert ratti to carat, gram and milligram instantly — with standard (pakki) and traditional (kachi) ratti conventions
Ratti ⇄ Carat ⇄ Gram Converter
Type a value in any field and the others update automatically.
1 pakki ratti = 0.91 carat = 182 mg — the convention used by most jewelers and gem sellers
Gemstone Weight by Body WeightTraditional guideline
A widely used rule of thumb in Jyotisha suggests a gemstone weight of about 1 carat for every 12 kg of body weight.
This is only a traditional guideline — some astrologers use 1 carat per 10 kg instead, and minimum effective weights differ by stone. Which gemstone suits you, and its final weight, should be decided from your birth chart.
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What is a Ratti?
Ratti is the traditional Indian unit of weight for gemstones, used in Jyotisha (Vedic astrology) and the Indian gem trade for centuries. It originally referred to the remarkably consistent weight of the ratti seed (Abrus precatorius, known as gunja or chirmi), which jewelers used as a natural counterweight on their balances.
Today, astrologers still prescribe gemstone weights in ratti — for example, a 5.25 ratti Pukhraj — while jewelers price and certify stones in carats. That is why converting between ratti, carat and gram accurately matters: a difference in convention can change the stone you buy by more than 30%.
Pakki Ratti vs Kachi Ratti
Two different ratti conventions are in use in India, and knowing which one your astrologer or jeweler means is essential before buying a stone.
Pakki Ratti (standard / jeweler's ratti)
The modern standardized ratti used by most jewelers, gem dealers and online stores: 1 pakki ratti = 0.91 carat = 182 milligrams = 0.182 grams. Some jewelers round this to 180 mg (0.90 carat), so it is worth confirming. This calculator uses the standard 0.91-carat ratti. In this convention, 1 carat ≈ 1.1 ratti (exactly 1.0989).
Kachi Ratti (traditional seed / desi ratti)
The older convention based on the actual gunja seed weight, defined as 96 ratti to 1 tola (11.664 g): 1 kachi ratti = 121.5 milligrams = 0.6075 carat. Traditional astrologers, especially when prescribing coral or pearl by older texts, may mean kachi ratti — 1 carat ≈ 1.65 kachi ratti. A prescription of 6 kachi ratti is only about 3.65 carats, versus 5.46 carats in pakki ratti.
Ratti to Carat Conversion Chart
Quick reference for common gemstone weights, from 1 to 12 ratti.
| Ratti | Carat | Gram | Milligram |
|---|---|---|---|
| 1 | 0.91 | 0.182 | 182 |
| 2 | 1.82 | 0.364 | 364 |
| 3 | 2.73 | 0.546 | 546 |
| 4 | 3.64 | 0.728 | 728 |
| 5 | 4.55 | 0.91 | 910 |
| 6 | 5.46 | 1.092 | 1092 |
| 7 | 6.37 | 1.274 | 1274 |
| 8 | 7.28 | 1.456 | 1456 |
| 9 | 8.19 | 1.638 | 1638 |
| 10 | 9.1 | 1.82 | 1820 |
| 11 | 10.01 | 2.002 | 2002 |
| 12 | 10.92 | 2.184 | 2184 |
Typical Gemstone Weights in Ratti
Commonly suggested wearing weights for the main Navagraha gemstones. Individual recommendations vary with the birth chart, planet strength and body weight.
Yellow Sapphire (Pukhraj)
Commonly 3–7 ratti; 5.25 ratti is a popular prescription for Jupiter.
Blue Sapphire (Neelam)
Commonly 3–6 ratti; Saturn's stone is usually trialed before regular wear.
Ruby (Manik)
Commonly 3–6 ratti for the Sun; quality matters more than size.
Emerald (Panna)
Commonly 3–6 ratti for Mercury.
Pearl (Moti)
Commonly 4–8 ratti for the Moon; natural pearls are often worn heavier.
Red Coral (Moonga)
Commonly 5–12 ratti for Mars; coral is light, so larger ratti sizes are usual.
Hessonite (Gomed)
Commonly 4–8 ratti for Rahu.
These ranges are general trade practice, not a prescription. Confirm which gemstone actually suits your kundli — and its ideal weight — with the Gemstone Calculator.
Frequently Asked Questions
How many carats is 1 ratti?
1 standard (pakki) ratti equals 0.91 carat, which is 182 milligrams or 0.182 grams. In the traditional kachi convention, 1 ratti equals 0.6075 carat (121.5 mg). Most jewelers today use the pakki ratti.
How many ratti is 1 carat?
1 carat equals about 1.1 pakki ratti (exactly 200 ÷ 182 = 1.0989 ratti), or about 1.65 kachi ratti. So a 5-carat gemstone is roughly 5.5 pakki ratti.
How do I convert ratti to gram?
Multiply ratti by 0.182 to get grams (pakki convention). For example, 5 ratti = 0.91 grams and 10 ratti = 1.82 grams. In the kachi convention, multiply by 0.1215 instead.
What is the difference between pakki ratti and kachi ratti?
Pakki ratti is the modern standardized jeweler's unit: 1 ratti = 0.91 carat = 182 mg. Kachi ratti is the traditional seed-based unit: 1 ratti = 0.6075 carat = 121.5 mg, from 96 ratti per tola. The same 'ratti' number therefore differs by about 50% between conventions, so always confirm which one is meant.
Which ratti do jewelers use for gemstones?
Most Indian jewelers and online gemstone sellers use the pakki (standard) ratti of 0.91 carat, though some round it to 180 mg. Certified stones are officially weighed in carats, so ask for the carat weight on the certificate and convert.
How much gemstone weight should I wear for my body weight?
A common traditional guideline is about 1 carat for every 12 kg of body weight — for example, 60 kg suggests around 5 carats (≈ 5.5 pakki ratti). Some astrologers use 1 carat per 10 kg. Treat this as a starting point and confirm the gemstone and weight from your birth chart.