Gold Price Calculator for Jewelry: How to Quote Metal Accurately

Step 1: Get the right spot price

Gold spot price is quoted in troy ounces (oz) on international markets. One troy ounce equals 31.1035 grams — not the 28.35 grams in a standard avoirdupois ounce. This distinction matters when converting to per-gram pricing.

Spot prices are updated continuously during trading hours. For quoting purposes, pulling a live rate at the time of quote creation is the most accurate approach. Using a price from memory or from last week introduces error — gold can move $50–100/oz in a week.

The conversion to per-gram:

If gold spot is $2,600 USD/oz:

For Canadian jewellers, multiply by the USD/CAD exchange rate. GemQuote fetches both live rates automatically.

Step 2: Apply the karat purity factor

The spot price refers to pure 24-karat gold (99.9% pure). Jewelry alloys are a percentage of pure gold mixed with other metals. The purity factor converts the per-gram price to your actual alloy:

Step 3: Account for casting or fabrication waste

This is the step that gets skipped most often and costs the most money over time.

When you cast or fabricate a piece, not all the metal you start with ends up in the finished piece. Sprues are cut off and recycled, filings are swept and reclaimed, and polishing removes surface material. The metal is not lost — it goes back into your scrap pile — but it does affect your cost calculation for this specific job.

If you buy metal at spot and reclaim scrap at a refiner's rate (typically 90–95% of spot), there is a real cost to every gram that passes through the shop as waste. For casting work, a 10–15% waste factor on the finished weight is a standard allowance. For fabrication from sheet and wire, 5–8% is more typical.

Skipping the waste factor on that piece underquotes your metal cost by $37.62. Across 20 similar jobs a month, that is $752 left on the table every month.

Pennyweight vs grams: which to use

Some older pricing systems and North American wholesale markets still use pennyweights (dwt). One pennyweight = 1.5552 grams. If your supplier quotes in dwt and you are working in grams, convert first.

There is no practical reason to prefer one unit over the other — consistency within your quoting system is what matters. Pick one and use it everywhere.

When gold moves between quote and job completion

A customer approves a quote on Monday. You order metal on Thursday. If gold moves 2% in that window on a job with $500 in gold content, that is a $10 cost swing — not catastrophic on one job, but meaningful at volume.

A few approaches jewellers use:

Lock price at quote: Quote at today's spot, note the lock date in the quote. If the job is approved within 30 days, the price stands. This is the most common approach for one-off custom work.

Quoted price subject to metal rates: Some shops build in a clause that the metal cost adjusts at the time of fabrication. This is more common for large pieces with high metal content.

Deposit covers material: Take a deposit that covers your material cost at time of quote. This effectively locks in your exposure.

GemQuote locks the gold price at quote creation and shows the date it was locked, so clients can see the market rate that was used.

The complete gold pricing formula

Every time you quote, this calculation needs to run against live spot. A static rate embedded in a spreadsheet from six months ago will not reflect where the market is today.

Try it: gold cost calculator

Enter your piece weight, karat and the current spot price. The calculator runs the full formula including waste factor.