Excel SLN Function
last modified October 5, 2026
The SLN function returns the straight-line depreciation of an asset
for one period. Straight-line depreciation spreads the depreciable amount of an
asset evenly across its useful life, which makes it the simplest of Excel's
depreciation functions. This tutorial explains the syntax and the underlying
formula, works through verified examples with cell references and different time
units, shows how to prorate a partial year, compares SLN with the
accelerated DB, DDB, and SYD methods, and
lists the errors you are most likely to encounter.
SLN Function Basics
The SLN function returns the straight-line depreciation of an asset
for one period. It takes three required arguments: cost, salvage value, and life.
The formula divides the depreciable amount equally over the asset's useful life,
so every period receives exactly the same charge.
| Component | Description |
|---|---|
| Function Name | SLN |
| Syntax | =SLN(cost, salvage, life) |
| Arguments | cost, salvage, life (all required) |
| Return Value | Depreciation per period |
This table outlines the key components of the SLN function. All
three arguments are required, there are no optional arguments, and the function
returns the depreciation amount for a single period.
| Argument | Meaning |
|---|---|
| cost | The initial cost of the asset. |
| salvage | The value at the end of the depreciation, called the salvage value. It may be zero. The salvage portion of the cost is never depreciated. |
| life | The number of periods over which the asset is depreciated, sometimes called the useful life. It must not be zero. |
life sets the time unit of the result: a life in years returns an
annual charge, a life in months returns a monthly charge. The arguments must be
numbers; text that does not look like a number produces a #VALUE!
error, and a life of zero produces a #DIV/0! error.
depreciation = (cost - salvage) / life
The depreciable amount is cost - salvage, and SLN
divides it into life equal parts. Multiplying the result by
life gives back the full depreciable amount, so an asset
depreciated for its whole life ends exactly at its salvage value.
Basic SLN Example
This example demonstrates the simplest use of the SLN function with hard-coded values. We'll calculate annual depreciation for an asset worth $10,000.
=SLN(10000, 1000, 5)
This formula calculates annual depreciation for a $10,000 asset with $1,000
salvage value over 5 years. The result is $1,800 per year. The calculation is
(cost - salvage) / life = (10000 - 1000) / 5.
Microsoft's documentation uses the same logic for a $30,000 asset with a $7,500
salvage value and 10 years of life: =SLN(30000, 7500, 10) returns
$2,250, because the $22,500 depreciable amount is divided into 10 equal yearly
charges.
SLN with Cell References
A more practical use of SLN involves referencing cells containing
the asset parameters. Here's an example with cell references.
| A | B |
|---|---|
| Cost: | 15000 |
| Salvage: | 3000 |
| Life (years): | 6 |
| Depreciation: | =SLN(B1,B2,B3) |
The table shows a spreadsheet with asset parameters in column B and the SLN formula in cell B4 that references these cells. This approach makes the worksheet more flexible and easier to update.
=SLN(B1,B2,B3)
This formula calculates annual depreciation for a $15,000 asset with $3,000 salvage value over 6 years. The result is $2,000 per year. Using cell references allows easy parameter changes without modifying the formula.
SLN with Monthly Depreciation
The SLN function can calculate depreciation for any time period by
adjusting the life parameter. This example shows monthly depreciation.
| A | B |
|---|---|
| Cost: | 8000 |
| Salvage: | 500 |
| Life (months): | 36 |
| Monthly Depr.: | =SLN(B1,B2,B3) |
This table demonstrates using SLN for monthly depreciation by expressing the asset life in months. The formula remains the same, but the interpretation of the result changes to monthly amounts.
=SLN(B1,B2,B3)
This formula calculates monthly depreciation for an $8,000 asset with $500 salvage value over 36 months. The result is $208.33 per month. The same function works for any time unit by adjusting the life parameter accordingly.
SLN with Zero Salvage Value
Many assets depreciate to zero value. This example shows SLN calculation when the salvage value is zero.
| A | B |
|---|---|
| Cost: | 5000 |
| Salvage: | 0 |
| Life (years): | 4 |
| Annual Depr.: | =SLN(B1,B2,B3) |
The table shows an asset that fully depreciates to zero value. The SLN formula simplifies to cost divided by life when salvage is zero. This is common for assets with no residual value.
=SLN(B1,B2,B3)
This formula calculates annual depreciation for a $5,000 asset with no salvage
value over 4 years. The result is $1,250 per year, since the calculation is
simply 5000/4 when the salvage value is zero. Salvage may be zero or positive;
it is the part of the cost that is never depreciated. Setting salvage equal to
cost makes SLN return 0, because there is nothing to write off.
SLN for Partial Year Depreciation
Assets are rarely placed in service on the first day of the year. Because
SLN returns a charge for one whole period, a partial year is
handled by scaling that charge to the number of months the asset was in use.
| A | B |
|---|---|
| Cost: | 12000 |
| Salvage: | 2000 |
| Life (years): | 5 |
| Months in service: | 9 |
| Partial-year Depr.: | =SLN(B1,B2,B3)*B4/12 |
The table stores the inputs in B1:B4 and the formula in B5. The annual charge
is (12000 - 2000) / 5 = 2000, and the asset was in service for 9
of the 12 months in its first year.
=SLN(B1,B2,B3)*B4/12
The formula returns $1,500, which is 2000 * 9 / 12. Scaling the
full-year charge by the fraction of the year in service gives the correct
partial-year depreciation. The rest of the life is then depreciated at the same
$2,000 per year, leaving only a short final stub to absorb the nine-month start.
SLN Compared to Other Depreciation Methods
The SLN function charges the same amount every period. The
accelerated methods DB, DDB, and SYD
charge more in the early years and less later. The table below compares all
four methods for the $10,000 asset with a $1,000 salvage value and a five-year
life used in the first example.
=SLN(10000, 1000, 5) =DB(10000, 1000, 5, 1) =DDB(10000, 1000, 5, 1) =SYD(10000, 1000, 5, 1)
| Year | SLN | DB | DDB | SYD |
|---|---|---|---|---|
| 1 | 1800.00 | 3690.00 | 4000.00 | 3000.00 |
| 2 | 1800.00 | 2328.39 | 2400.00 | 2400.00 |
| 3 | 1800.00 | 1469.21 | 1440.00 | 1800.00 |
| 4 | 1800.00 | 927.07 | 864.00 | 1200.00 |
| 5 | 1800.00 | 584.98 | 296.00 | 600.00 |
All four methods allocate the same $9,000 depreciable amount
(cost - salvage) over the five years. SLN charges
$1,800 every year. SYD declines steadily from $3,000 to $600.
DDB starts at $4,000 and, in year 5, is clamped to $296 so that
the book value stops exactly at the $1,000 salvage value. DB
applies a fixed rate of 0.369 to a shrinking book value, so its charges fall
from $3,690 to $585 and its five charges total about $8,999.66, a few cents
below $9,000, because DB rounds its rate to three decimal places.
Choose the method that matches how the asset is consumed. Use SLN
when the benefit is spread evenly, which gives flat, predictable expense in
every period. Use DDB or DB when the asset loses
value fastest in the early years, which is common for tax schedules. Use
SYD for a moderate acceleration that is gentler than
declining-balance. Each accelerated method front-loads the expense, while
SLN keeps it constant.
SLN Errors and Troubleshooting
| Cause | Symptom | Fix |
|---|---|---|
| life is zero | #DIV/0! error | Give life a positive, non-zero number of periods |
| An argument is text that is not a number | #VALUE! error | Make sure the referenced cells contain numbers; ISNUMBER can verify |
| Referenced cell is empty | Empty cost or salvage counts as 0; an empty life gives #DIV/0! | Fill in all three inputs before using the formula |
| life is negative | Negative amount instead of an error | Use a positive life; only zero raises #DIV/0! |
| salvage is greater than cost | Negative depreciation | Check the values; the asset must cost more than its salvage value |
| Arguments entered in the wrong order | Plausible but incorrect result | The order is cost, salvage, life |
| Referenced cell contains an error | The same error is passed through | Fix the source cell, or wrap the formula in IFERROR |
Because SLN is a single division, its own errors are limited: a
zero life raises #DIV/0! and non-numeric text raises
#VALUE!. A negative life does not raise an error; it
silently returns a negative charge, so check the sign of the result whenever it
looks wrong.
The SLN function gives you the simplest and most predictable
depreciation calculation in Excel: one division that spreads
cost - salvage evenly across life periods. Keep the
three arguments in order, express life in the time unit you want
back, and prorate the full-year charge when an asset is in service for only
part of a year. When value really does fall evenly, SLN is the
method to use; when an asset loses value quickly up front, switch to
DB, DDB, or SYD instead. With these
rules in hand you can build accurate schedules and choose the method that fits
your accounting or tax needs.
Author
List all Excel Formulas.