What is Depreciation?

Depreciation is a key accounting concept that affects financial statements and tax calculations for businesses. For a UK audience, understanding depreciation is essential for accurately reflecting the value of assets and managing tax liabilities.


Key Aspects of Depreciation:

  1. Definition:
    • Depreciation is the systematic allocation of the cost of a tangible fixed asset over its useful life. It represents the wearing out, consumption, or other reduction in the useful economic life of an asset.
  2. Purpose:
    • Reflecting Asset Value: Depreciation helps in accurately representing the value of an asset on the balance sheet by accounting for the decline in its value over time.
    • Matching Expenses to Revenue: It ensures that the cost of an asset is matched to the revenue it generates, adhering to the matching principle in accounting.
    • Tax Deduction: Depreciation can be used as a tax-deductible expense, reducing the taxable profit of a business.
  3. Methods of Depreciation:
    • Straight-Line Depreciation: The simplest and most common method, where the asset’s cost is spread evenly over its useful life.
      • Formula: (Cost of Asset – Residual Value) / Useful Life
      • Example: An asset costing £10,000 with a residual value of £1,000 and a useful life of 5 years would have an annual depreciation expense of (£10,000 – £1,000) / 5 = £1,800.
    • Reducing Balance Method: Also known as declining balance, where a fixed percentage is applied to the reducing book value of the asset each year.
      • Example: If the same £10,000 asset is depreciated at 20% per year, the first year’s depreciation would be £10,000 * 20% = £2,000, the second year would be (£10,000 – £2,000) * 20% = £1,600, and so on.
    • Units of Production: Depreciation based on the asset’s usage, output, or activity levels.
      • Formula: (Cost of Asset – Residual Value) / Total Estimated Units of Production * Units Produced in the Period
      • Example: If the asset is expected to produce 100,000 units and actually produces 10,000 units in a year, and the cost less residual value is £9,000, the annual depreciation is £9,000 / 100,000 * 10,000 = £900.
    • Sum-of-the-Years’-Digits: An accelerated depreciation method that results in higher depreciation expenses in the earlier years and lower expenses in the later years.
      • Example: For an asset with a 5-year life, the sum of the years’ digits is 1+2+3+4+5=15. The first year’s depreciation would be (5/15) * (Cost – Residual Value), the second year would be (4/15) * (Cost – Residual Value), and so on.
  4. Impact on Financial Statements:
    • Income Statement: Depreciation is recorded as an expense, reducing the net income of the business.
    • Balance Sheet: Depreciated value (net book value) of the asset is shown on the balance sheet, reducing the asset’s original cost by the accumulated depreciation.
    • Cash Flow Statement: Depreciation is a non-cash expense, added back to the net income in the operating activities section of the cash flow statement.
  5. Capital Allowances:
    • In the UK, businesses can claim capital allowances on certain capital expenditures, which allows them to deduct a portion of the cost from their taxable profits. This is the tax equivalent of depreciation.
    • Annual Investment Allowance (AIA): Allows businesses to deduct the full value of certain qualifying assets up to a specified limit.
    • Writing Down Allowance (WDA): Allows businesses to deduct a percentage of the cost of assets over time.
  6. Example:A UK-based company purchases a piece of machinery for £50,000 with an expected useful life of 10 years and no residual value. Using the straight-line method:
    • Annual Depreciation: £50,000 / 10 = £5,000
    • Each year, £5,000 is recorded as a depreciation expense on the income statement, and the machinery’s value on the balance sheet is reduced accordingly.


Depreciation is a fundamental concept in accounting that affects how businesses report asset values and manage tax liabilities. For UK businesses, understanding the different methods of depreciation and their impact on financial statements is crucial for accurate financial reporting and effective tax planning. By appropriately depreciating assets, businesses can ensure that their financial records reflect the true economic value of their assets and comply with tax regulations.