Diminishing value method
Front-loaded depreciation — a bigger claim early, shrinking each year.
The diminishing value method claims a larger decline in the early years of an asset’s life and less each year after, by applying the rate to the remaining value rather than the cost. The ATO formula is: base value × (days held ÷ 365) × (200% ÷ effective life), or 150% instead of 200% for assets you first held before 10 May 2006.
Because the rate applies to the written-down value, the asset never quite reaches zero under this method — the remainder is dealt with on disposal through the balancing adjustment, or written off when it falls below a threshold. A short effective life can produce a rate of 100% or more, in which case the decline is capped at the opening value.
Worked example
A $2,000 laptop with a two-year life gives a rate of 200% ÷ 2 = 100%, so the whole $2,000 declines in year one and the schedule stops. A $30,000 car with an eight-year life gives 25%: $7,500 in year one, then 25% of the remaining $22,500 = $5,625 in year two, and so on.
Common mistake
Applying the rate to the original cost every year. That is prime cost arithmetic with a diminishing-value rate, and it over-claims from year two onward.
Grounded in ATO — Prime cost and diminishing value methods guidance. Figures last checked . General information, not tax advice.
Related terms
Prime cost method
Straight-line depreciation — the same deduction each year of the effective life.
Effective life
How many years an asset is expected to be used — the base of every depreciation rate.
Balancing adjustment
What happens to the leftover value when you sell or scrap a depreciating asset.
Depreciation (decline in value)
Claiming the cost of a big asset gradually over its life.
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