How Gold Is Priced: From Grams to Karats and Global Market Rates

Gold prices you see in news tickers come from the global spot market quoted per troy ounce (31.1035 g). Retail buyers and jewelers convert that into grams (or traditional units like tola and vori) and then adjust for purity, making charges, and taxes. This guide shows the math—step by step.

1) Spot Price: the Global Anchor

The spot price is the current wholesale market price for investment-grade gold (usually 0.999 fine) per troy ounce. One troy ounce equals 31.1035 grams (note: this is different from the common avoirdupois ounce of 28.35 g).

• Per-gram reference: spot_per_gram = spot_per_ounce / 31.1035
• For traditional units, see: Tola, Vori and Other Traditional Gold Measurements.

2) Purity: Karats and Fineness

Spot price refers to pure gold. Jewelry is an alloy. Convert karats to fineness to get the pure-gold fraction:

• Fineness formula: fineness = karat / 24 (e.g., 18K → 0.75; 14K → 0.585; 22K → 0.9167)
• Refresh on karats and hallmarks: Understanding Gold Hallmarks: 24K, 22K, 18K, 14K
• Why many choose 18K for balance: Why 18K Gold Is the Perfect Balance

3) The Core Formula (Investment Value of Gold Content)

To estimate the bullion value of the gold inside a piece of jewelry:

pure_gold_weight_g = total_weight_g × (karat / 24)
bullion_value = pure_gold_weight_g × spot_per_gram

This gives the starting point for value based on metal content alone (not the final retail price).

4) Retail Price: Beyond Metal Value

Finished jewelry typically exceeds bullion value because of:

• Making/Design charges (craftsmanship, labor, finishing)
• Brand/design premium (signature houses, limited collections)
• Overheads and distribution (wastage allowance, inventory risk)
• Taxes/duties (VAT/GST/imports depending on country)

5) Worked Examples

Example A: 18K Ring, 5.0 g

1. Assume spot = $X per troy ounce → per gram = X / 31.1035.
2. Pure gold fraction (18K) = 18/24 = 0.75.
3. Pure gold weight = 5.0 × 0.75 = 3.75 g.
4. Metal value = 3.75 × (X / 31.1035).
5. Add making charge + brand premium + tax to reach retail price.

Example B: 22K Bangle, 30 g (South Asian market)

1. Fineness 22K = 22/24 = 0.9167.
2. Pure gold weight = 30 × 0.9167 ≈ 27.50 g.
3. Metal value = 27.50 × (X / 31.1035).
4. Local quotes may be given per tola/vori—convert using 1 tola ≈ 11.6638 g.

6) Quick Reference Table

7) Practical Tips

• Always check the hallmark (e.g., 750 for 18K) to confirm purity.
• Compare metal value to the ticket price to understand the making premium.
• For white gold, note any rhodium plating cycles (maintenance cost).
• When buying abroad, ask for weight in grams alongside local units.

Related Reading

• Understanding Gold Hallmarks: 24K, 22K, 18K, 14K
• Why 18K Gold Is the Perfect Balance Between Purity and Durability
• Tola, Vori and Other Traditional Gold Measurements