All-in sustaining cost (AISC) is the number that shows which gold and base-metal producers can keep operating when the metal price rolls over. This guide breaks down what AISC captures beyond simple cash cost, how the industry cost curve works, and how to read a producer's AISC margin and breakeven price.
All-in sustaining cost (AISC) is a per-unit cost metric — usually quoted in dollars per ounce for precious metals or dollars per pound for base metals like copper. It was formalized by the World Gold Council in 2013 as a voluntary, non-GAAP standard so investors could compare producers on a more complete basis than the older "cash cost" figure.
The core idea is simple. A mine's headline cash cost (sometimes called C1) only captures what it takes to dig and process ore in a given period. But keeping a mine running over its life costs more than that: you have to replace worn equipment, spend on exploration just to hold your reserve base steady, fund the corporate office, and set aside money to eventually close the site. AISC folds those recurring, unavoidable costs into a single number, so $/oz AISC is a much closer read on what an operation genuinely costs to sustain.
The distinction that trips people up is sustaining versus growth. AISC includes the spending required to maintain current production at the existing operation. It deliberately excludes spending aimed at expanding output or building something new — that lands in a separate, broader figure the World Gold Council calls All-In Cost (AIC).
| Included in AISC | Excluded from AISC |
|---|---|
| On-site mining, processing and refining costs | Growth / expansion capital (new mines, mill expansions) |
| Royalties and production taxes | Exploration to find new deposits |
| Sustaining capital expenditure (equipment replacement) | Financing costs and interest |
| Sustaining exploration to maintain reserves | Income taxes |
| Corporate general & administrative (G&A) | Impairments and one-off write-downs |
| Reclamation and remediation (accretion & amortization) | Working-capital swings and M&A costs |
By-product credits are typically netted off. A gold mine that also sells copper or silver, for example, subtracts revenue from those by-products, which can pull reported AISC down sharply. That is worth remembering when comparing a single-metal operation against a polymetallic one — the accounting choice, not the geology, can explain part of the gap.
Because AISC captures the recurring cost of staying in business, it functions as an approximate breakeven line. If a producer's realized selling price sits comfortably above its AISC, the operation generates cash it can use to fund growth, pay down debt, or return to shareholders. If the metal price falls toward or below AISC, that cushion disappears — and, critically, the sustaining spend inside AISC is hard to defer for long without shrinking the reserve base or letting equipment degrade.
This is why analysts describe AISC as a downturn stress test rather than just a profitability ratio. The question it helps answer is descriptive, not predictive: at today's price, how much margin does this operation actually have before it stops covering its own upkeep?
Rank every producer of a given metal from lowest AISC to highest, and you get the industry cost curve — an upward-sloping line where each producer occupies a position based on how cheaply it can sustain output. The metal's market price is drawn as a horizontal line across the chart.
The mechanics of a downturn become visual on this curve. When the price line drops, it sweeps down through the curve from the right. The highest-AISC producers — those on the far right — are the first to fall below the price line and lose their margin. Low-AISC producers on the left keep a positive margin far longer. In industry shorthand, first-quartile (lowest-cost) producers have staying power: they can keep operating profitably at prices that push higher-cost peers underwater. This is a structural observation about cost position, not a claim about any individual company's prospects.
Two derived figures make the cost curve usable at the single-company level:
= realized price − AISC (per ounce or pound). This is the cushion between what the metal sells for and what it costs to sustain the operation.≈ AISC. The approximate metal price at which the AISC margin falls to zero.The illustrative table below ranks five hypothetical producers along a cost curve and shows how their margins compress as the gold price falls from an assumed $1,900/oz to $1,500/oz. The numbers are made up to demonstrate the mechanics, not to describe any real miner.
| Producer | AISC ($/oz) | Margin at $1,900 | Margin at $1,500 |
|---|---|---|---|
| A (low-cost) | 950 | +950 | +550 |
| B | 1,150 | +750 | +350 |
| C (mid-curve) | 1,400 | +500 | +100 |
| D | 1,700 | +200 | −200 |
| E (high-cost) | 1,950 | −50 | −450 |
Read left to right, the pattern is the whole point. At $1,900, only Producer E is underwater. Drop the price to $1,500 and Producer D falls below breakeven too, while the low-AISC producers still hold a comfortable margin. The higher a producer sits on the cost curve, the faster a price decline erases its cushion — which is exactly what "which miners survive a downturn" is asking.
AISC is useful, but it is one input among many and it has real limits:
Used carefully, AISC and the cost curve describe cost position and margin resilience. They do not, on their own, value a company or forecast a metal price — those depend on reserves, balance sheet, jurisdiction, and factors well beyond a single cost line.
Quintarthai's screener surfaces producer cost and margin data — including AISC per unit and the implied AISC margin against prevailing metal prices — alongside reserve and financial-statement fields drawn from public filings (SEDAR+ / EDGAR) and licensed market data, so you can rank mining producers along the cost curve and examine breakeven levels as one factual input in your own research.
AEM in the free Core dashboard at quintarthai.com/app.