How to price jewelry by weight on Shopify: formula and examples
Published 2026-10-24
Pricing jewelry by weight means the price follows the metal. When the market moves, so should your price. The method is the same for a gold ring, a silver chain or a platinum band. Here it is, step by step.
Step 1: Get the metal value per gram
Spot prices are quoted per troy ounce. One troy ounce is 31.1035 grams (not the 28.35 grams of an ordinary ounce, a common mix-up). Divide the spot price by 31.1035 to get the price per gram.
For example, if spot gold is $3,110.35 per troy ounce, that is $100 per gram. These numbers are illustrative, chosen to keep the maths simple, not a current price.
Some markets sell by other units. One tola is about 11.6638 grams, and pennyweight (dwt) is one twentieth of a troy ounce.
Step 2: Adjust for purity
The spot price is for pure metal. Jewelry is usually an alloy, so you multiply by the purity fraction:
| Alloy | Purity fraction |
|---|---|
| 24K gold (fine) | 0.999 |
| 22K gold | 0.916 |
| 18K gold | 0.750 |
| 14K gold | 0.585 |
| 10K gold | 0.417 |
| Sterling silver (925) | 0.925 |
A frequent mistake is using the 24K rate for an 18K piece. That overprices it by a third.
Step 3: Add your own charges
Metal value is only the start. Most sellers then add some or all of these, depending on how they run their business:
- Making charge: the cost of labor and craft, as a percentage or a flat amount.
- Wastage: metal lost in manufacturing, usually a percentage.
- Markup: your margin.
- Tax: where it applies to your sales.
A worked example
An 18K gold pendant weighing 5 grams, using the illustrative $100 per gram rate from above, with these example charges (yours will differ):
| Part | Calculation | Amount |
|---|---|---|
| Metal value | 5 g × 0.750 × $100 | $375.00 |
| Making charge | 12% of metal value | $45.00 |
| Wastage | 3% of metal value | $11.25 |
| Subtotal | $431.25 | |
| Markup | 10% of subtotal | $43.13 |
| Price before tax | $474.38 |
If spot gold rises 2%, the metal value rises by $7.50 and every charge that is a percentage of it moves too. Do that across hundreds of products and you can see why doing it by hand stops working.
Step 4: Keep it current
The formula is easy. Keeping hundreds of prices current as the market moves is the hard part. Our guide to updating gold prices on Shopify automatically covers the options.