Grams to Carats Converter
Convert grams (g) to carats (ct) instantly. Uses the standard metric carat where 1 carat = 0.2 grams, so 1 gram = 5 carats. Includes reverse carats to grams, decimal control, jewelry presets, and a quick reference table.
Full original guide (expanded)
Grams to Carats Converter
Convert stone and jewelry weights from grams (g) to carats (ct) using the exact metric definition: 1 g = 5 ct. Includes reverse conversion for listing diamonds or gemstones in grams.
Convert weight
Jewelry presets (g):
Result
Carats: –
Factor used: 1 g = 5 ct
Reverse (ct → g)
Grams to carats formula
The modern metric carat (used worldwide for diamonds and gemstones) is defined as exactly 0.2 grams. That means:
1 ct = 0.2 g1 g = 1 ÷ 0.2 = 5 ct
So the working formula is:
carats = grams × 5
Example: 0.35 g × 5 = 1.75 ct.
Reverse:
grams = carats × 0.2
Quick reference table
| Grams (g) | Carats (ct) |
|---|---|
| 0.10 g | 0.50 ct |
| 0.20 g | 1.00 ct |
| 0.35 g | 1.75 ct |
| 0.50 g | 2.50 ct |
| 1.00 g | 5.00 ct |
| 2.00 g | 10.00 ct |
| 5.00 g | 25.00 ct |
FAQ
Is this different from “karat”?
Yes. “Carat” (ct) is a unit of mass for gemstones. “Karat” (K) is a unit of gold purity. This tool is for gemstone weight.
Why is 1 g = 5 ct so neat?
Because the metric carat was deliberately fixed at 0.2 g to make decimal conversions easy, especially for trading and valuation.
Formula (LaTeX) + variables + units
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1 ct = 0.2 g 1 g = 1 ÷ 0.2 = 5 ct
grams = carats × 0.2
- No variables provided in audit spec.
- 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
Last code update: 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.