DDB applies a constant rate — double the straight-line rate — to an asset’s shrinking book value each year, producing a different front-loaded pattern than sum-of-the-years’-digits.
How it works
Doubling the straight-line rate (2 divided by useful life) and applying it to the book value remaining at the start of each year gives that year’s depreciation, with the book value never allowed to fall below salvage value.
What this does not include
This does not include the common practice of switching to straight-line depreciation partway through an asset’s life once straight-line would produce a larger deduction than continuing DDB — a refinement many businesses apply that this calculator doesn’t model.
How to use this calculator
- Enter cost, salvage value, useful life, and the year you want to calculate.
Frequently asked questions
Why does DDB depreciation stop exactly at salvage value?
Because accounting rules don’t allow an asset to be depreciated below its estimated salvage value — the method caps the final year(s) of depreciation to land exactly there.
Is DDB more aggressive than sum-of-the-years’-digits?
Typically yes in the very first year, though the two methods’ schedules cross over at different points depending on the specific useful life — neither is uniformly more accelerated across every single year.
Does DDB apply to salvage value differently than straight-line?
Yes — straight-line spreads the cost-minus-salvage amount evenly, while DDB ignores salvage value in the rate calculation itself and only uses it as a floor that stops depreciation once book value reaches it.
