Quick answer
Depreciation is the systematic allocation of a depreciable asset’s cost, less its residual value, over its useful life. It recognizes cost as the asset’s benefits are consumed; it does not remeasure the asset to market value.
A long-lived asset can provide benefits over many reporting periods. Expensing its entire cost immediately would charge the acquisition period for benefits used in later periods. The depreciation method should reflect how the business expects to consume those benefits.
Why depreciation matters
Depreciation makes each period’s performance more representative by recognizing part of the asset’s cost in the periods that receive its benefits. Without that allocation, the acquisition period could bear the entire cost while later periods report revenue generated with the asset but no related asset-use expense.
This is one application of the limited idea commonly called the matching principle: depreciation recognizes consumption of the asset’s benefits without requiring a direct match to a particular dollar of revenue. The practical task is to allocate the depreciable amount systematically according to the expected consumption pattern, not to estimate the asset’s market value.
The four building blocks
- Cost
- The amount recorded when the asset is acquired and made ready for use.
- Residual value
- The expected value remaining at the end of the asset’s useful life, after relevant disposal assumptions.
- Useful life
- The period or output over which the entity expects to consume the asset’s benefits.
- Depreciable amount
- Cost less residual value—the amount allocated over the useful life.
Choose a method that matches the pattern of use
The building blocks determine the amount available to allocate. The method determines when that amount becomes expense. A business selects the method that best reflects the pattern in which it expects to consume the asset’s benefits; it does not select a method simply to produce the preferred profit result.
- Straight-line
- Use when the expected benefit is reasonably even from period to period. The same amount is allocated in each full period.
- Diminishing balance
- Use when the expected benefit is greater in earlier periods. A selected rate is applied to the opening carrying amount, producing a larger expense early and a smaller expense later.
- Units of production
- Use when measured output or activity is a better representation of consumption than the passage of time. First calculate a rate per expected unit, then apply it to actual use for the period.
One asset, three consumption patterns
Assume equipment costs $50,000, has a $5,000 residual value, a five-year useful life, and capacity of 100,000 units. It produces 22,000 units in the first year. A 30% diminishing-balance rate is used only to illustrate an early-heavy pattern.
| Method | First-year calculation | Expense | Pattern represented |
|---|---|---|---|
| Straight-line | ($50,000 − $5,000) ÷ 5 years | $9,000 | Even benefit across the five years |
| Diminishing balance | $50,000 opening carrying amount × 30% | $15,000 | More benefit in the earlier years |
| Units of production | ($45,000 ÷ 100,000 units) × 22,000 units | $9,900 | Benefit follows measured output |
These amounts differ because the methods represent different patterns, not because one has found a different cost. All three begin with the same $45,000 depreciable amount. Over the asset’s life, depreciation stops once the applicable depreciable amount has been allocated; a diminishing-balance calculation is not allowed to push the asset below its residual-value floor under the stated estimate.
Decide when allocation starts and what is being allocated
A purchase date does not by itself settle the first depreciation period. The business determines when the asset is available for its intended use, applies its supported partial-period convention, and considers whether significant parts have different consumption patterns. A building and a major component inside it, for example, may require separate lives or methods when the applicable requirements and facts support that treatment.
With that reasoning in place, Maple Tech can now choose straight-line: its stated facts assume the equipment’s benefits are consumed evenly over 60 months.
Maple Tech’s March allocation
One month of straight-line depreciation
Equipment cost $12,000; residual value $0; useful life 60 months. The equipment was available for use on March 3, 2026. Maple’s stated policy records a full month of depreciation for assets that become available for use during the month.
($12,000 − $0) ÷ 60 months = $200 per month
| Account | Debit | Credit |
|---|---|---|
| Depreciation Expense | 200 | |
| Accumulated Depreciation — Equipment | 200 |
Depreciation Expense records March’s allocation. Accumulated Depreciation is a contra-asset that keeps the equipment’s original recorded cost visible while offsetting part of it.
| Line item | Amount |
|---|---|
| Equipment, at recorded cost | 12,000 |
| Less: Accumulated depreciation | (200) |
| Equipment, net carrying amount | 11,800 |
Financial-statement effect
| Statement | Account | Effect | Timing |
|---|---|---|---|
| Income statement | Depreciation Expense | Expense increases by $200; March profit decreases by $200 | For March |
| Balance sheet | Accumulated Depreciation | Contra-asset increases by $200; net equipment becomes $11,800 | At March 31 |
| Cash flow statement | Depreciation | The depreciation entry has no cash effect; it is added back in an indirect operating bridge | The separate equipment acquisition is a March investing cash outflow |
In practice, the facts and reporting framework determine when depreciation starts, which method and estimates to use, and whether significant parts of an asset must be depreciated separately.
Keep nearby ideas separate
- Estimate changes update future allocations when a useful life, residual value, or consumption pattern changes based on new information; they do not automatically rewrite prior entries.
- Impairment asks whether an asset’s recorded amount should be reduced because the amount expected to be recovered has fallen below it. It is not another depreciation method.
- Canadian tax capital cost allowance (CCA) serves a tax purpose. A tax deduction is not interchangeable with book depreciation for financial reporting.
Allocation, not valuation
Equipment can rise or fall in market value while straight-line depreciation continues under the stated estimates. The $11,800 carrying amount is a recorded accounting amount, not a market-price appraisal.
See PP&E and Intangible Assets for the acquisition context and Adjusting Entries for the full March period-end sequence.