Precision Luxury

How to Calculate Precious Metal Yield, Casting Fill, and Setting Labor in Jewelry Manufacturing

The core formulas behind jewelry and watch production, worked in grams, minutes, and microns so you can run them on your own bench.

Precious metal yield is the first number to get right because metal is 70 to 85 percent of a fine jewelry piece cost. Yield equals finished part weight divided by total metal issued, times 100. Cast a run of 100 rings at 4.20 g each finished, and you shipped 420 g of product. If you issued 560 g of 18K casting grain, yield is 420 divided by 560, which is 75 percent. The other 140 g is not lost, it becomes sprue, buttons, and grindings that route to scrap recovery. Run this through the Precious Metal Yield calculator per alloy, since 14K, 18K, and platinum behave differently.

Alloy density drives every weight conversion, so convert wax to metal before you ever pour. Metal weight equals wax pattern weight times the density ratio of alloy to wax. Injection wax runs about 0.95 g per cm3. 18K yellow is roughly 15.6 g per cm3, so the ratio is about 16.4. A 0.28 g wax model becomes 0.28 times 16.4, which is 4.59 g in 18K. In platinum at 21.4 g per cm3 the same wax casts near 6.3 g. Get the ratio wrong by 5 percent on a 5,000 piece run and your metal issue estimate is off by hundreds of grams.

Casting tree utilization tells you how much of a flask you actually filled with product versus sprue. Tree yield equals summed part weight divided by total tree weight including sprue and button. A tree holding 60 pieces at 4.2 g is 252 g of product. If the full tree with a 90 g sprue system and button weighs 360 g, utilization is 252 divided by 360, which is 70 percent. Push part count per tree from 60 to 80 without growing the sprue and you lift utilization to 76 percent, cutting the metal tied up in each pour. The Casting Tree Utilization calculator runs this per flask size.

Stone setting labor is a time calculation, not a guess. Total setting minutes equals stone count times minutes per stone by type, plus a fixed layout allowance. Prong setting a solitaire runs 8 to 15 minutes, a bezel 6 to 10, and micro pave averages 1.5 to 3 minutes per stone once the seats are cut. A halo ring with 1 center at 12 minutes plus 24 pave stones at 2.2 minutes plus a 5 minute layout is 12 plus 52.8 plus 5, which is 69.8 minutes. Feed those per stone rates into the Stone Setting Labor calculator to build a defensible bench time per piece.

Polishing and finishing time scales with surface area and finish grade, not piece count alone. A typical estimate is base minutes per piece times a complexity factor. A plain band might take 4 minutes at a mirror finish, while an openwork filigree piece with 12 pierced windows takes 4 times a 2.5 factor, which is 10 minutes. Add tripoli, rouge, and ultrasonic steps and a multi stage cycle reaches 15 to 20 minutes. The Polishing Time calculator lets you set stage counts and per stage rates so a 500 piece batch estimate does not drift by hours.

Plating cost hinges on deposited mass, which comes straight from Faraday's law. Deposited metal in grams equals current in amps times time in hours times 3.6, times the electrochemical equivalent, times bath efficiency. For hard gold at roughly 2.45 g per amp hour and 90 percent efficiency, 10 amps for 6 minutes deposits 10 times 0.1 times 2.45 times 0.9, which is 2.2 g of gold across the load. At a 2.5 micron target on 40 dm2 of surface, you can back-calculate required amp hours and dose the Plating Bath Cost calculator to price gold per piece to four decimal places.

Tie the whole flow together with a mass balance so nothing walks off unaccounted. Metal in equals product out plus recoverable scrap plus process loss. On a 560 g issue producing 420 g of rings, if scrap recovery captures 132 g of clean turnings and sprue, unaccounted loss is 560 minus 420 minus 132, which is 8 g, about 1.4 percent. Polishing sweeps, filings, and bench lemel typically account for 1 to 3 percent, and refiners return 90 to 98 percent of that. Feed captured weights into the Scrap Recovery Value calculator to close the loop and confirm your yield number is real, not assumed.

Published 2026-07-01.