How to use the depreciation calculator
- Enter the asset cost, which is the original purchase price including taxes and delivery.
- Set the salvage value, the estimated amount you can sell the asset for at the end of its useful life.
- Specify the useful life in whole years.
- Choose between straight-line (equal expense every year) or declining balance (higher expense early on).
- Read the computed annual depreciation and the remaining book value below the form.
How straight-line depreciation works
Straight-line depreciation divides the depreciable base evenly across the asset's useful life. The formula is:
Annual Depreciation = (Cost - Salvage Value) / Useful Life
For example, a machine purchased for $10,000 with a $1,000 salvage value and a 5-year life has a depreciable base of $9,000. Dividing $9,000 by 5 gives an annual expense of $1,800. After the first year the book value drops to $8,200, after the second to $6,400, and so on until it reaches exactly $1,000 at the end of year five.
This method is the simplest and most widely used because it produces a predictable, constant charge against income each period. It suits assets that wear out uniformly over time, such as office furniture or building improvements.
How declining balance depreciation works
The double declining balance method applies a fixed percentage to the remaining book value each year rather than to the original cost. The rate is twice the straight-line rate:
Rate = 2 / Useful Life
Using the same $10,000 machine with a 5-year life, the straight-line rate is 20 percent, so the declining balance rate is 40 percent. In year one the expense is 40 percent of $10,000, which equals $4,000, leaving a book value of $6,000. In year two the expense is 40 percent of $6,000, or $2,400, leaving $3,600.
A key rule is that the book value must never fall below the salvage value. If applying the full rate would push the balance under the salvage figure, the depreciation for that year is capped at the difference between the current book value and the salvage value. This method front-loads expenses, which better matches assets like vehicles or computers that lose more utility in their early years.
Reference table: straight-line examples
The table below shows common scenarios calculated with the straight-line method. Each row assumes no mid-year convention.
| Cost | Salvage | Life | Annual Expense | Book Value Year 1 |
|---|---|---|---|---|
| $1,000 | $0 | 5 yr | $200 | $800 |
| $5,000 | $500 | 10 yr | $450 | $4,550 |
| $12,000 | $2,000 | 4 yr | $2,500 | $9,500 |
| $50,000 | $5,000 | 7 yr | $6,428.57 | $43,571.43 |
These figures help verify manual calculations or compare different asset classes side by side.
When to use each method
Straight-line is appropriate when an asset provides roughly equal benefit each year. Buildings, fences and leasehold improvements typically follow this pattern. Tax authorities in many jurisdictions also default to straight-line for certain property classes, making it the path of least resistance for compliance.
Declining balance suits technology, vehicles and machinery that become obsolete or require heavy maintenance as they age. By recognizing more expense early, a business reduces taxable income sooner, which improves near-term cash flow. However, not all tax systems permit accelerated methods for every asset type, so always check local regulations before choosing.
If you need to project what an investment will grow to over time rather than shrink, a future value calculator handles compound growth. For breaking down periodic debt payments, see the loan calculator.
Common mistakes to avoid
One frequent error is confusing salvage value with zero. Even if you plan to discard an asset, its scrap or resale value may not be zero. Entering the wrong salvage figure skews every subsequent year.
Another mistake is applying the declining balance rate to the original cost instead of the current book value. The rate must multiply the remaining balance each period, producing a shrinking dollar amount over time.
Finally, forgetting the salvage floor in declining balance leads to negative or unrealistically low book values. The depreciation in any given year should never reduce the balance below the stated salvage value. This depreciation calculator enforces that cap automatically so you do not have to track it manually.
Worked examples
Each result below was produced by the same code the tool runs, so you can check your own numbers against them.
| Example | Input | Result |
|---|---|---|
| Office laptop, straight-line | Asset cost: 1500; Salvage value: 300; Useful life (years): 4; Method: sl | Annual depreciation: 300; Total depreciable amount: 1,200; Book value after 1 year: 1,200; Book value at end of life: 300 |
| Delivery van, declining balance | Asset cost: 45000; Salvage value: 5000; Useful life (years): 6; Method: db | Depreciation rate: 33.3333333333%; Year 1 depreciation: 15,000; Book value after 1 year: 30,000; Book value at end of life: 5,000 |
| Warehouse shelving, straight-line | Asset cost: 8000; Salvage value: 0; Useful life (years): 10; Method: sl | Annual depreciation: 800; Total depreciable amount: 8,000; Book value after 1 year: 7,200; Book value at end of life: 0 |
| Server rack, declining balance | Asset cost: 25000; Salvage value: 2500; Useful life (years): 5; Method: db | Depreciation rate: 40%; Year 1 depreciation: 10,000; Book value after 1 year: 15,000; Book value at end of life: 2,500 |
FAQ
What is a depreciation calculator used for?
It computes how much value a tangible asset loses each year over its useful life. Businesses use the result to record depreciation expense on financial statements and tax returns.
What is the difference between straight-line and declining balance?
Straight-line charges the same amount every year. Declining balance charges a higher amount in early years and less later, reflecting faster loss of utility.
Can salvage value be zero?
Yes. If an asset will have no resale or scrap value at the end of its useful life, enter zero as the salvage value.
Does this tool handle partial years?
No. This depreciation calculator uses full-year periods without mid-year or mid-month conventions. For partial first years, prorate the annual result manually based on the months in service.
Is declining balance the same as MACRS?
Not exactly. MACRS is a specific US tax system that uses declining balance rates but also applies half-year or mid-quarter conventions and switches to straight-line when advantageous. This tool computes pure mathematical declining balance.
Why does the book value stop at the salvage value?
An asset cannot be depreciated below what it is expected to be worth at disposal. The calculation caps total depreciation so the ending book value equals the salvage value.