Alloy Composition to Mass
Turn an alloy specification in mass percent into the mass of each element for a batch, with per-element yields for melting losses, or melt corrections.
Per element the target mass and the charge after yield, the balance element filled to 100 %, the total charge and expected loss, or in adjust mode the addition of each element to reach the target.
Example: Cu bal / Sn 10 % (95 % yield) / Zn 2 % (90 %) for 500 kg: weigh 440 kg Cu, 52.6 kg Sn and 11.1 kg Zn — 503.7 kg charged for 500 kg of bronze. Raising C from 0.4 to 0.8 % in 950 kg: add 3.83 kg.
Percent of the batch,
divided by the yield.
How the weigh sheet is built, what yield does, and how a melt correction is computed.
Weigh sheet
Each element’s mass is the batch mass × its mass percent ÷ 100; one element marked "bal" takes whatever is left to 100 %. If the percentages do not sum to 100 and nothing is marked balance, the page says so rather than rescaling.
Yield
Some of an addition is lost to oxidation and slag. A yield (recovery) percent per element inflates the charge: charge = mass ÷ yield, so 50 kg of tin at 95 % yield is 52.6 kg charged. The total charge exceeds the batch by the expected loss.
Correcting a melt
To raise element c to target t in a melt of mass M by adding the pure element, x = M(t − c) ÷ (1 − t) — the added mass raises both numerator and denominator. Each element is computed against the current melt independently; several additions dilute each other slightly, so iterate once. A negative result means the element is over target. All percentages are your specification; no alloy grades are embedded. Nothing leaves the browser; the same four anonymous usage counts as the rest of the site apply.
SOURCES
- mass = batch × percent ÷ 100; charge = mass ÷ yield; addition to raise c → t in a melt of mass M: x = M(t − c)/(1 − t); no alloy grades embedded
Last reviewed 21 September 2026. How results are checked: How we verify.