Double Declining Balance Method: Formula & Examples
Double declining balance method
Some assets lose most of their value the moment you start using them — a new laptop, a delivery van, a machine that's obsolete in a few years. The double declining balance method matches that reality by front-loading depreciation: big expenses early, smaller ones later. This guide gives you the correct formula, a full worked schedule, and a clear view of when to use it.
The double declining balance (DDB) method is a form of accelerated depreciation that charges more expense in an asset's early years and less later on. Each year's depreciation is the asset's book value at the start of the year × twice the straight-line rate.
The DDB rate is 2 ÷ useful life. Salvage value isn't subtracted in the yearly calculation, but the asset is never depreciated below its salvage value — so the final year's charge is often reduced to land exactly on salvage.
What is the double declining balance method?
The DDB method allocates a larger portion of an asset's cost to the earlier years of its useful life, producing higher depreciation early and lower depreciation later. It reflects how assets like vehicles, computers and machinery lose value fastest when they're new. It's one of several depreciation methods, and the most common form of accelerated (declining-balance) depreciation.
Double declining balance formula
Annual depreciation = Book value at start of year × DDB rate
DDB rate = 2 × (1 ÷ useful life) = 2 ÷ useful life
Two things make DDB different from straight-line depreciation: the rate is doubled, and it's applied to the reducing book value (cost minus accumulated depreciation) each year — not to a fixed depreciable base. Because the base shrinks every year, so does the depreciation charge.
The DDB rate is 2 ÷ useful life — for a 10-year asset that's 2 ÷ 10 = 20%, not "10 ÷ 2". And the rate is applied to the opening book value, not to (cost − salvage). Salvage only matters as a floor at the end.
How to calculate DDB depreciation
- Find the asset's cost. Purchase price plus anything needed to get it ready for use (installation, shipping).
- Estimate the useful life in years, and the salvage value (what it's worth at the end).
- Work out the DDB rate: 2 ÷ useful life. A 5-year asset gives 2 ÷ 5 = 40%.
- Apply the rate to the opening book value each year to get that year's depreciation, then reduce the book value by it.
- Stop at salvage. In the final years, cap the charge so book value never drops below salvage value.
Worked example (with full schedule)
An asset costs ₹10,000, has a 5-year useful life and a ₹1,000 salvage value. The DDB rate is 2 ÷ 5 = 40%. Applying 40% to the opening book value each year:
| Year | Opening book value | Rate | Depreciation | Closing book value |
|---|---|---|---|---|
| 1 | 10,000 | 40% | 4,000 | 6,000 |
| 2 | 6,000 | 40% | 2,400 | 3,600 |
| 3 | 3,600 | 40% | 1,440 | 2,160 |
| 4 | 2,160 | 40% | 864 | 1,296 |
| 5 | 1,296 | capped | 296 | 1,000 (salvage) |
At 40%, year 5 would be 1,296 × 40% = ₹518, dropping book value to ₹778 — below the ₹1,000 salvage floor. So the charge is limited to ₹296 (1,296 − 1,000), leaving book value exactly at salvage. Total depreciation over the five years is ₹9,000, the full depreciable amount (10,000 − 1,000).
DDB vs straight-line vs units of production
| Aspect | Double declining balance | Straight-line | Units of production |
|---|---|---|---|
| Basis | Opening book value × 2× SL rate | Equal amount each year | Actual output or usage |
| Expense pattern | High early, falls over time | Constant | Varies with usage |
| Best for | Fast-depreciating assets (tech, vehicles) | Evenly used assets (buildings) | Usage-driven assets (machinery by output) |
| Complexity | Higher — recalculated yearly | Lowest | Depends on tracking usage |
| End of life | Often switches to SL to hit salvage | Lands on salvage naturally | Tracks usage to the end |
Advantages and disadvantages
| Advantages | Disadvantages |
|---|---|
| Front-loads expense to match heavy early usage | More complex than straight-line |
| Defers tax, improving early-year cash flow | Lowers reported profits in early years |
| Reflects the fast value loss of tech and vehicles | Unsuitable for evenly used assets |
| Supports the matching principle | Usually needs a switch to straight-line near the end |
When to use — and when not to
- Use it for assets that lose value quickly or become obsolete early — computers, servers, vehicles, high-tech equipment.
- Avoid it for assets consumed evenly over time, like buildings, where straight-line is a better fit.
- Check tax rules — some jurisdictions don't permit DDB for tax purposes, so the book and tax methods may differ.
- Consider usage-based assets — if wear tracks output rather than time, units of production is more accurate.
Accounting treatment under IFRS and US GAAP
DDB is an accepted depreciation method under both frameworks, provided it reflects the pattern in which the asset's economic benefits are consumed.
| Point | IFRS (IAS 16) | US GAAP |
|---|---|---|
| Is DDB allowed? | Yes — diminishing (reducing) balance is permitted | Yes — a common accelerated method |
| Method must reflect | The consumption pattern of benefits | The consumption pattern of benefits |
| Review of method, life & residual | At least at each year-end | At least annually |
| Disclosure | Method, carrying amount, accumulated depreciation and any changes | Method, depreciation expense, accumulated depreciation and changes |
In the financial statements, the annual depreciation charge appears as an expense in the income statement, with the method and assumptions (useful lives, salvage values, rates) disclosed in the notes. Any change in method, life or salvage estimate is disclosed with its justification and effect. For the underlying rules, see our IAS 16 practice questions.
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Browse ACCA books ACCA online courseFrequently asked questions
What is the double declining balance method?
How do you calculate the DDB rate?
Does the DDB method use salvage value?
Is the double declining balance method allowed under IFRS and US GAAP?
What's the difference between DDB and straight-line depreciation?
Why would a company use the DDB method?
When do you switch from DDB to straight-line?
Conclusion
The double declining balance method front-loads depreciation to mirror how quickly many assets lose value. Get two things right and it's straightforward: the rate is 2 ÷ useful life, and it's applied to the reducing book value each year — never taking the asset below its salvage value. For fast-depreciating assets it gives a truer picture of cost and a useful early tax deferral; for evenly used assets, straight-line is usually the better choice.
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