Depreciation Calculator · Practical guide
Sum of Years' Digits Depreciation Method
An accelerated method with a built-in schedule: year one takes the biggest slice, and each later year takes one digit less.
At a glance
Quick answer
Sum of years' digits (SYD) depreciation multiplies the depreciable base by a fraction: remaining life divided by the sum of the years' digits. For a 5-year life the digits sum to 1+2+3+4+5 = 15, so year one claims 5/15 of the base, year two 4/15, and so on.
Interactive tool
Depreciation Calculator
Enter your own values, then compare the result with the examples below.
Results
| Year | Depreciation | Accumulated Depreciation | Book Value |
|---|
Example: $50,000 Cost, $5,000 Salvage, 5-Year Life
The depreciable base is $45,000. Each year takes its fraction of that base:
| Year | Fraction | Depreciation | Book value |
|---|---|---|---|
| 1 | 5/15 | $15,000 | $35,000 |
| 2 | 4/15 | $12,000 | $23,000 |
| 3 | 3/15 | $9,000 | $14,000 |
| 4 | 2/15 | $6,000 | $8,000 |
| 5 | 1/15 | $3,000 | $5,000 |
Book value lands exactly on the $5,000 salvage value — no capping is needed because the fractions always sum to the full base.
SYD vs the Other Methods
SYD front-loads expense like declining balance but follows a smoother, fully predictable schedule. Year one here is $15,000, between straight line's flat $9,000 and double declining's $20,000 — a middle path for assets that wear faster early but not dramatically so.
Quick Shortcut for the Digit Sum
For a life of n years, the sum of digits is n(n+1)/2 — a 5-year life gives 5 × 6 / 2 = 15, and a 10-year life gives 55. Use the SYD tab above to generate the complete schedule for any cost, salvage, and life.
Frequently Asked Questions
How do I compute the sum of years' digits quickly?
Use the formula n(n+1)/2 where n is the useful life in years. A 5-year asset sums to 15 and a 10-year asset sums to 55 — no need to add digits one by one.
Is sum of years' digits an accelerated method?
Yes. It expenses more in early years than straight line, but less aggressively than double declining balance. All three methods total the same depreciation over the full life.
Does SYD ever depreciate below salvage value?
No. The fractions are applied to cost minus salvage, so the schedule ends exactly at salvage value by construction.
When would I choose SYD over straight line?
When the asset delivers more value or loses more market value in its early years — production machinery is a common case — but you want a smoother expense curve than double declining balance.