Carat to Grams Converter
Convert gemstone or jewelry weights from carats (ct) to grams (g) using the standard metric carat where 1 ct = 0.2 g. Includes reverse grams → carats for appraisals, sourcing, and e-commerce product pages.
Convert weight
Jewelry presets:
Result
Grams: –
Factor used: 1 ct = 0.2 g
Reverse (g → ct)
Carat to grams formula
The modern metric carat used in jewelry is defined as exactly 0.2 grams:
1 carat (ct) = 0.2 grams (g)
So to convert:
grams = carats × 0.2
Example: a 1.25 ct diamond × 0.2 = 0.25 g.
To go the other way:
carats = grams ÷ 0.2 = grams × 5
Quick reference table
| Carats (ct) | Grams (g) |
|---|---|
| 0.25 ct | 0.05 g |
| 0.50 ct | 0.10 g |
| 0.75 ct | 0.15 g |
| 1.00 ct | 0.20 g |
| 1.50 ct | 0.30 g |
| 2.00 ct | 0.40 g |
| 5.00 ct | 1.00 g |
FAQ
Is this for gold or diamonds?
Carat as 0.2 g is the gemstone/jewelry carat — typically for diamonds, gemstones, and pearls. Gold purity “karat” (with a K) is different and not a weight unit.
Why is 5 carats = 1 gram?
Because 1 carat is 0.2 g, so 1 ÷ 0.2 = 5. That’s a handy rule to remember: 5 ct = 1 g.
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
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Formula (extracted text)
1 carat (ct) = 0.2 grams (g)
Formula (extracted text)
grams = carats × 0.2
Formula (extracted text)
carats = grams ÷ 0.2 = grams × 5
Variables and units
- No variables provided in audit spec.
Sources (authoritative):
- NIST — Weights and measures — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/weights-and-measures - NIST — SI units — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/owm/metric-si/si-units
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
- Initial audit spec draft generated from HTML extraction (review required).
- Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
- Confirm sources are authoritative and relevant to the calculator methodology.