Calculate accelerated depreciation with the sum-of-the-years’ digits method, with the expense and book value for each year. Enter your values; the result updates as you type, with the method shown below.
About this calculator
Sum-of-the-years’-digits depreciation is an accounting method that spreads an asset’s cost over its life. It is an accelerated method: depreciation is highest in the first year and falls each year.
Enter the asset cost, the salvage value and the life (or units). The calculator shows the depreciation schedule and the first-period amount.
When to use it
- Valuing equipment that loses value fast at first.
- Comparing depreciation methods.
- Preparing accounts or a tax return.
- Studying accounting.
How to read the result
Year k depreciation = (cost − salvage) × remaining life / sum of the years. For 5 years, the sum is 15, so year 1 takes 5/15.
Tax rules decide which methods and lives are allowed for each asset.
Mistakes to avoid
- Using a method not accepted by tax rules.
- Forgetting the salvage value.
- Mixing up years and units.
Formula
Expense year t = (cost − salvage) × (n − t + 1) / (n(n + 1)/2)
Worked example
Cost 20,000, salvage 2,000, 5 years: year 1 is 6,000 (5/15 of 18,000).
Frequently asked questions
Why use an accelerated method?
It matches assets that lose more value early, like vehicles or computers.
Is it allowed for tax in France?
France uses straight-line or declining balance; this method is mainly US/IFRS.
What is the sum of digits?
For 5 years: 1 + 2 + 3 + 4 + 5 = 15.
Which method is best?
It depends on how the asset loses value and on tax rules.
Does it change total depreciation?
No, only how it is spread over time.
Can I switch methods?
Usually only under specific accounting rules.
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Results are estimates for information only. Check important figures with a professional.