Depreciation: SLN, DDB & SYD

Excel Formulas › Financial

All versionsSLNDDBSYD

Excel has built-in functions for the common depreciation methods: SLN spreads cost evenly (straight-line), while DDB and SYD front-load it (accelerated). Pick the one your accounting requires.


Quick formula: straight-line yearly depreciation (cost, salvage, life):
=SLN(cost, salvage, life)
SLN(10000, 1000, 5) = 1800 per year. DDB and SYD take the same inputs plus the period number.

Functions used (tap for the full reference guide):

The example

A $10,000 asset, $1,000 salvage, 5-year life — year 1 depreciation by method.

AB
1MethodYear 1
2SLN (straight-line)$1,800
3DDB (double-declining)$4,000
4SYD (sum-of-years)$3,000

The formula

Year-1 depreciation, three ways:

=SLN(10000, 1000, 5) → 1800 (same every year) =DDB(10000, 1000, 5, 1) → 4000 (year 1) =SYD(10000, 1000, 5, 1) → 3000 (year 1)

How it works

Three methods, same cost/salvage/life inputs:

  1. SLN(cost, salvage, life)straight-line: the same amount every year, (cost - salvage)/life.
  2. DDB(cost, salvage, life, period)double-declining balance: accelerated, biggest deduction in year 1, tapering off.
  3. SYD(cost, salvage, life, period)sum-of-years’-digits: also accelerated but smoother than DDB.
  4. DDB and SYD need the period (which year); SLN doesn’t, since every year is identical.

Build a full schedule by filling the period (1, 2, 3…) down a column and the chosen function across. All methods total the same depreciable base (cost − salvage) over the life — they just distribute it differently across the years.

Try it: interactive demo

Live demo

$10,000 cost, $1,000 salvage, 5-yr life. Pick a year and method.

Depreciation:

Variations

Straight-line per month

Divide the annual SLN by 12:

=SLN(cost, salvage, life) / 12

Variable declining (VDB)

More control over the rate and partial periods:

=VDB(cost, salvage, life, start, end)

Total to date

Sum the periods so far for accumulated depreciation.

Pitfalls & errors

DDB can dip below salvage. DDB doesn’t automatically stop at the salvage value in later years — cap it, or switch to SLN for the tail (what VDB can automate).

Period is required for DDB/SYD. Forgetting the 4th argument errors. SLN has no period because it’s constant.

Match the method to your rules. Tax and book depreciation may require a specific method — check the requirement before choosing.

Practice workbook

📊
Download the free Depreciation: SLN, DDB & SYD practice workbook
Live SLN/DDB/SYD by year with a full schedule, the per-month and VDB variants, plus 4 challenges with answers. No sign-up required.

Frequently asked questions

How do I calculate depreciation in Excel?
Use SLN for straight-line (=SLN(cost, salvage, life)), or DDB and SYD for accelerated methods, which also take the period number, e.g. =DDB(cost, salvage, life, year).
What's the difference between SLN, DDB and SYD?
SLN spreads the cost evenly each year. DDB (double-declining balance) and SYD (sum-of-years-digits) front-load depreciation, with the largest deductions in the early years.
Why does DDB go below the salvage value?
DDB doesn't automatically stop at salvage. Cap the result at the remaining depreciable amount, or use VDB which can switch to straight-line for the final years.

Stop fighting formulas. Learn them in a day.

This recipe is one of hundreds of real-world formulas we teach. Our Excel Formulas & Functions class covers lookups, logic, text, and dynamic arrays hands-on — live in Dallas–Fort Worth, Houston, Austin, Oklahoma City, Denver, or online.

See the Formulas & Functions Class

Related formulas: Present value (PV) · ROI & payback period · Compound interest

Function references: SLN · DDB · SYD