Straight Line Depreciation Calculator
Produce the full year-by-year schedule, handle part-year purchases correctly, and see exactly where book value sits at the end of every period.
Straight Line Depreciation Calculator
Results recalculate instantly on every keystroke. Nothing you type is transmitted.
What this result does not account for
- Assumes value declines evenly, which rarely matches how assets actually lose worth.
- Uses annual periods with monthly pro-rating rather than tax conventions.
- A single salvage estimate drives the whole schedule and is rarely accurate.
In short: A $540,000 asset with $60,000 salvage over five years depreciates at $96,000 a year, 20.00% of the depreciable base. Book value falls from $540,000 to $60,000 in equal steps, reaching salvage exactly at the end of year five.
Formula
The simplest method in accounting, and the one most likely to be applied with the wrong rate base — the rate on cost and the rate on the depreciable base differ whenever salvage is above zero.
Worked Example
- Find the depreciable base. $540,000 cost less $60,000 salvage is $480,000. Salvage is excluded because it is expected to be recovered on disposal.
- Divide by useful life. $480,000 ÷ 5 is $96,000 a year, or $8,000 a month — the figure posted in management accounts.
- Adjust for a part first year. An asset owned nine months takes $72,000 in year one, and the remaining $24,000 extends into a sixth accounting year.
- Track book value each year. $540,000 falls to $444,000, $348,000, $252,000, $156,000 and finally $60,000 — equal steps throughout.
- Stop at salvage. Depreciation ceases at $60,000. Assets still in use past that point carry no further charge, flattering reported profit.
The rate quoted for straight line depreciation is ambiguous more often than people realise. This asset depreciates at 20.00% of its depreciable base but only 17.78% of its original cost, and both figures are defensible descriptions of the same $96,000 charge. The gap exists entirely because salvage is above zero, and it widens as salvage grows: an asset with 40% residual value depreciates at 20% of base and 12% of cost. When a schedule is inherited or a rate is quoted without its basis, checking which denominator was used is worth the thirty seconds, because applying a base rate to cost overstates the annual charge by exactly the salvage proportion.
Strengths & Limits Of This Model
Where this engine is strong
- Reports the rate on both cost and depreciable base, avoiding a common error.
- Handles part-year purchases and shows the resulting extra period.
- Prints the full schedule rather than only the annual charge.
Where it stops
- Cannot model mid-quarter or half-year tax conventions.
- Does not handle revaluation or impairment.
Practical Use Cases
Building a fixed asset register
The monthly figure is what gets posted. Annual figures divided at year end create reconciliation differences in interim accounts.
Handling a mid-year purchase
Part-year depreciation extends the schedule into an additional accounting year, which surprises people preparing five-year forecasts for a five-year asset.
Explaining deferred tax
Book and tax depreciation differ by method and life. The gap creates deferred tax that reverses over the asset life.
Estimating maintenance capital requirements
Straight line depreciation is the usual proxy for replacement spending. Compare it to actual capex with the Cash Flow Calculator.
Methodology & Editorial Standards
Straight line depreciation allocates the depreciable base evenly across the useful life, and it is the dominant method in financial reporting because an even charge produces stable comparable earnings and requires no assumption about the pattern of economic decline. The engine computes the annual and monthly charge, reports the rate against both the depreciable base and original cost since those differ whenever salvage is above zero, and produces the full year-by-year schedule of charges and closing book values. Part-year ownership in the first period is handled on a monthly basis, which extends the schedule into an additional accounting year and is a common source of confusion when a five-year asset appears across six reporting periods. Depreciation stops once book value reaches salvage; assets remaining in service beyond that point continue to appear on the balance sheet at their residual value while generating no further charge, which flatters the reported profit of any business running its asset base past the estimated life. Because tax rules frequently mandate a different method and life for the same asset, the difference between book and tax depreciation is among the most common sources of deferred tax. The engine implements the standard published formula for this calculation. Inputs are validated for domain and sign before evaluation, and any undefined case returns an em-dash rather than a spurious value.
Computation runs in IEEE-754 double precision at full internal precision; rounding to two decimal places occurs strictly at the display layer, so no cumulative drift enters the result. All monetary outputs use accounting presentation — grouped thousands, two decimals, negatives in parentheses — so figures can be transcribed directly into a model or working paper. Division-by-zero and out-of-domain inputs return an em-dash rather than a misleading number.
This engine was reconciled against an independent reference implementation and hand-verified for the worked example above before release. Our full five-stage review process is published on the About Us page.
Disclaimer. This calculator is provided for informational and modelling purposes only and does not constitute financial, tax, legal, medical, or engineering advice. Verify all figures with a qualified professional before acting on them.
Straight Line Depreciation Calculator — 20 Expert FAQs
20 analyst-written answers to the questions practitioners actually ask — optimised for voice and answer-engine retrieval.
How is straight line depreciation calculated?
Cost less salvage, divided by useful life. Here $480,000 ÷ 5 is $96,000 a year.
Why exclude salvage from the base?
Because it is expected to be recovered on disposal. Depreciating it would write off value the business still holds.
What is the depreciation rate here?
20.00% of the depreciable base, or 17.78% of original cost. Both describe the same $96,000 charge.
Which rate should I quote?
State the basis explicitly. Applying a base rate to cost overstates the charge by exactly the salvage proportion.
How do I handle a mid-year purchase?
Pro-rate by months owned. Nine months gives $72,000, and the remaining $24,000 extends into an additional year.
Why does a five-year asset appear over six years?
Because a part first year pushes the balance forward. The total written off is unchanged; only the number of periods increases.
What happens when book value reaches salvage?
Depreciation stops. The asset stays on the balance sheet at salvage with no further charge, even if still in use.
Does that flatter profit?
Yes. A business running assets past their estimated life reports no depreciation on them while still consuming their remaining value.
Should salvage be estimated at zero?
Often, for simplicity and prudence. It raises the annual charge and avoids an estimate that is difficult to support.
Why is straight line so widely used?
It produces stable earnings, needs no assumption about the decline pattern, and is the easiest to audit and explain.
Can tax and accounts use different methods?
Yes, and they usually do. The difference between book and tax depreciation is a common source of deferred tax.
Is depreciation a cash cost?
No. It allocates a past outflow, which is why it is added back to compute operating cash flow and excluded from EBITDA.
What monthly figure should I post?
$8,000 here. Posting annual figures and dividing at year end creates reconciliation differences in interim accounts.
How do I choose a useful life?
By expected economic use, supported by experience with similar assets. Tax codes often prescribe lives that differ from the accounting estimate.
What if I change the estimated life?
Depreciate the remaining book value over the revised remaining life. Prior periods are not restated — it is a change in estimate.
Does depreciation affect the cash flow statement?
Only as an add-back. It reduces profit without consuming cash, so it is reversed in the operating section.
Is this straight line depreciation calculator free to use?
Yes. It is free, requires no account, and has no usage limits. ApexConverter is funded by contextual advertising, never by selling user data.
Is my data sent to a server?
No. The engine runs as Vanilla JavaScript inside your browser under our Zero-Server Client-Side Execution model. Your figures are computed locally and are never transmitted, logged, or stored.
How accurate is this calculator?
It applies the standard closed-form formula in IEEE-754 double precision, rounding only at the display layer. The engine is reconciled against an independent reference implementation before release.
Does it work on mobile?
Yes. The interface is mobile-first with numeric keypad hints and is tested down to a 320-pixel viewport with no horizontal scrolling.