How do you calculate casting lot cost?

Multiply the number of castings by the variable cost per casting and the allocation factor, then add fixed setup cost. For 240 castings at $68 each with 100% allocation plus $1,800 setup, the total is $18,120 and the cost per casting is $75.50.

Why does cost per casting fall with bigger lots?

Fixed setup cost is shared across the whole lot. The $1,800 setup adds $7.50 per piece across 240 castings; double the lot to 480 and that same setup adds only $3.75, so each casting gets cheaper even with variable cost unchanged.

What is the lot cost allocation factor?

It scales the variable portion to capture overhead burden, yield loss, or a markup you want folded into per-piece cost. At 100% it passes variable cost straight through; raise it above 100% to load extra burden onto each casting.

What is a good cost per casting?

There's no universal target — it depends on alloy, weight, and complexity. Use the calculator to compare your number against the quoted price and your competitors; the per-casting figure is what determines whether the job is profitable at the offered price.

How do I lower cost per casting?

Spread fixed setup over a larger lot, cut variable cost by improving yield and reducing scrap, or trim the allocation burden. The biggest lever on a short run is almost always lot size, because setup dominates per-piece cost there.

Does this include scrap and rework?

Only if you've built them into the variable cost per casting or the allocation factor. The calculator doesn't model scrap separately, so fold your expected scrap rate into the per-piece variable figure for an honest total.

Foundry & Forging calculator

Casting Lot Cost Calculator

Casting Lot Cost rolls up what a single foundry production lot actually costs — the variable cost of metal, energy, and labor per casting, scaled by an allocation factor, plus the fixed cost of pattern setup, mold prep, and furnace charging that the whole lot shares. Estimators and foundry cost engineers use it to quote jobs and to see how fixed setup spreads thinner as lot size grows. The headline insight is the per-casting cost: a large lot amortizes the setup across many pieces, while a small lot carries it on few, which is why short runs cost more each. It turns scattered cost inputs into a defensible quote.

What this calculator does

Estimate total cost for a casting lot including metal, molding, cores, melt, cleaning, inspection, rework, and fixed setup cost.
Use it when quoting a lot, comparing suppliers, setting minimum order quantities, or reviewing actual cost versus estimate.
It totals a casting lot's cost by multiplying piece count, variable cost per casting, and an allocation factor, then adding fixed setup, and divides to get cost per casting.

Formula used

Total casting lot cost = castings in the lot × variable cost per casting × lot cost allocation + fixed lot setup cost
Cost per casting = total cost ÷ castings in the lot

Inputs explained

Castings in the lot:
Variable cost per casting:
Lot cost allocation:
Fixed lot setup cost:

How to use the result

Use it when quoting a casting job, comparing lot sizes, or deciding the run quantity that makes a price competitive.
It assumes a flat variable cost per casting, but real per-piece cost shifts with yield, scrap rate, and metal price, so update the variable figure as those move.

Current U.S. benchmarks

The producer price index for steel mill products stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 3,569 primary metal manufacturing establishments employing about 354,911 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate casting lot cost? Multiply the number of castings by the variable cost per casting and the allocation factor, then add fixed setup cost. For 240 castings at $68 each with 100% allocation plus $1,800 setup, the total is $18,120 and the cost per casting is $75.50.
Why does cost per casting fall with bigger lots? Fixed setup cost is shared across the whole lot. The $1,800 setup adds $7.50 per piece across 240 castings; double the lot to 480 and that same setup adds only $3.75, so each casting gets cheaper even with variable cost unchanged.
What is the lot cost allocation factor? It scales the variable portion to capture overhead burden, yield loss, or a markup you want folded into per-piece cost. At 100% it passes variable cost straight through; raise it above 100% to load extra burden onto each casting.
What is a good cost per casting? There's no universal target — it depends on alloy, weight, and complexity. Use the calculator to compare your number against the quoted price and your competitors; the per-casting figure is what determines whether the job is profitable at the offered price.
How do I lower cost per casting? Spread fixed setup over a larger lot, cut variable cost by improving yield and reducing scrap, or trim the allocation burden. The biggest lever on a short run is almost always lot size, because setup dominates per-piece cost there.

Last reviewed 2026-05-12.