Depletion allocates the capitalized cost of an extractive natural resource as recoverable units are produced or sold.
Depletion is the systematic allocation of the capitalized cost of an extractive natural resource as recoverable units are produced or sold. It is used for mineral deposits, oil and gas properties, timber, and similar wasting assets whose economic benefit is consumed through extraction.
Accounting depletion is a cost-allocation process. It is not the same as physical reserve decline, environmental damage, impairment, depreciation of equipment, or the U.S. tax method called percentage depletion.
A simplified units-of-production calculation is:
The relevant units can be extracted, cut, or sold depending on the accounting or tax purpose and inventory method. The policy should be applied consistently and reconciled to production, reserve, and inventory records.
The base depends on the industry and reporting framework. It can include eligible acquisition, exploration, development, and restoration-related amounts, less residual or salvage value and costs allocated to non-depletable assets.
| Item | Possible treatment | Why it requires analysis |
|---|---|---|
| Mineral or resource rights | Capitalized resource-property cost | Ownership and economic-interest terms matter |
| Exploration and evaluation | Capitalized or expensed under the applicable policy | IFRS 6 permits specific policy choices and impairment requirements |
| Development costs | Often included when capitalization criteria are met | Productive and unsuccessful expenditures can differ by framework and industry method |
| Wells, machinery, and processing equipment | Often depreciated separately | Useful life can differ from reserve life |
| Restoration and abandonment | Can affect asset and liability measurement | Present-value, timing, and legal-obligation estimates change |
| Land residual value | Excluded from the depletable portion where appropriate | Surface land can retain value after extraction |
The formula should not be applied to a single undifferentiated project cost without identifying which costs relate to the resource, production assets, exploration, inventory, and closure obligations.
A quarry has a $5,000,000 depletable resource cost, an estimated $500,000 residual value, and 900,000 tons of recoverable stone.
During the year, the quarry extracts 100,000 tons and sells 80,000 tons. Ignoring other production costs:
If extracted stone is inventory, the $500,000 is first assigned to production. The portion associated with 80,000 tons sold is $400,000 and enters cost of sales; $100,000 remains in the 20,000 tons of ending inventory.
| Allocation | Tons | Depletion cost |
|---|---|---|
| Sold output | 80,000 | $400,000 |
| Ending inventory | 20,000 | $100,000 |
| Total extracted | 100,000 | $500,000 |
Tax cost depletion may use units sold and tax-basis definitions under IRS rules. That result should not be substituted automatically for the financial-reporting inventory calculation.
Recoverable units are estimates based on geological, engineering, economic, legal, and operating information. New drilling, commodity prices, technology, recovery methods, permits, ownership changes, or production history can revise those estimates.
Suppose that after recognizing depletion, remaining depletable cost is $4,000,000 and updated recoverable units are 700,000 tons. The revised rate is:
An estimate change generally affects current and future allocation under the applicable framework; it is not automatically an error in prior statements. A prior estimate can still be erroneous if it ignored available evidence or used unsupported data.
| Concept | Applies to | Measurement idea |
|---|---|---|
| Depletion | Natural-resource property | Units extracted or sold relative to recoverable reserves |
| Depreciation | Tangible production assets | Time, output, or another consumption pattern |
| Amortization | Finite-lived intangible or similar rights | Useful life and consumption of economic benefits |
| Impairment | Assets whose carrying amount may not be recoverable | Comparison required by the applicable impairment model |
An oil field can therefore report depletion on capitalized resource costs, depreciation on equipment, amortization on qualifying rights, and impairment if recoverability deteriorates. Combining the expenses as DD&A on the income statement does not make the underlying calculations identical.
U.S. federal tax law provides two distinct depletion concepts:
Percentage depletion is a tax rule, not a book units-of-production estimate. It is unavailable for some resources and taxpayers, restricted for oil and gas, and can produce an amount different from cost depletion. Timber uses cost depletion rather than percentage depletion under the IRS guidance cited below.
Tax basis, economic interest, resource type, gross income from the property, taxable-income limits, and prior deductions all require review. Tax calculations should be made from current law and return instructions.
Review:
A falling depletion rate is not necessarily favorable. It may reflect reserve additions, acquisitions, higher estimated recovery, or cost-pool changes. A rising rate may reflect downward reserve revisions or new development costs. Cash cost per unit, finding and development cost, production volume, and commodity prices provide additional context.
This page is educational and does not provide accounting, engineering, environmental, tax, legal, valuation, or investment advice.