Accounting & Bookkeeping

What is Straight-Line Depreciation?

A depreciation method that allocates an equal amount of an asset's cost as expense in each period of its useful life.

How It Works

Straight-Line Depreciation (SLM) is the simplest and most widely used depreciation method. It spreads the depreciable amount (cost minus salvage value) evenly over the asset's useful life. It's appropriate when the asset provides equal benefit in each period (e.g., furniture, buildings, office equipment). Under the Companies Act 2013 Schedule II, SLM rates are prescribed for different asset classes. For income tax purposes (Section 32), India prescribes Written Down Value (WDV) rates, so companies often maintain separate depreciation schedules for books (SLM) and tax (WDV), creating deferred tax differences. SLM is preferred for financial reporting because it's simple, consistent, and easy to understand. It's less suitable for assets that lose value faster in early years (where WDV or accelerated methods are more accurate).

Formula

Annual Depreciation = (Cost − Salvage Value) ÷ Useful Life in Years; Depreciation Rate = (1 ÷ Useful Life) × 100%

Real-World Example

Computer purchased for ₹80,000. Salvage value: ₹5,000. Useful life (Schedule II): 3 years. Annual depreciation: (₹80,000 − ₹5,000) ÷ 3 = ₹25,000/year. Year 1 NBV: ₹55,000. Year 2 NBV: ₹30,000. Year 3 NBV: ₹5,000 (salvage). Monthly charge: ₹25,000 ÷ 12 = ₹2,083.

Why It Matters

1

Ensures accurate financial reporting and record-keeping

2

Helps maintain regulatory and tax compliance

3

Enables better-informed business decisions

4

Improves operational efficiency and cash flow management

Frequently Asked Questions

When should I use straight-line vs WDV depreciation?

Use SLM when: the asset provides uniform benefit over its life (buildings, furniture), you want simple and consistent charges, or for financial reporting compliance. Use WDV when: the asset loses value faster initially (vehicles, technology), for tax purposes (mandatory in India under Section 32), or when matching higher maintenance costs in later years.

What happens when an asset is purchased mid-year?

Depreciation is prorated for the period of use. If a ₹1,20,000 asset with 5-year life is bought on October 1 (half-year remaining): first year depreciation = ₹24,000 × 6/12 = ₹12,000. Some companies use a half-year convention (50% in first and last year) for simplicity.

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