Every asset a business buys — a delivery van, a laptop, a CNC machine — quietly loses value from the day it arrives. That gradual loss is called depreciation, and putting a number on it matters for taxes, honest bookkeeping, and knowing what your equipment is truly worth on paper.

The Depreciation Calculator on this page turns that slow slide into clean, exact numbers. Enter the asset’s purchase cost, the salvage value you expect at the end of its life, and the number of years you plan to use it. Then choose one of three standard methods: straight-line, double-declining balance, or sum-of-the-years’ digits.

You will get the first-year depreciation expense, a monthly figure, and the book value remaining after year one, along with the formula behind the result so you can verify every number by hand.

What Does the Depreciation Calculator Do?

The Depreciation Calculator spreads an asset’s cost across its useful life using the depreciation method you select. It starts from the depreciable amount — the cost minus the salvage value — and assigns a portion of that amount to each year.

For the straight-line method the yearly amount is constant. For the accelerated methods it is front-loaded, with bigger charges early on. The calculator shows the first-year expense, the monthly equivalent, and the book value after year one so you can see the effect immediately.

How to Use the Depreciation Calculator

Start with the asset cost: the full price you paid, including delivery and installation if you count those in the asset’s basis. Next enter the salvage value, your best estimate of what the asset will be worth when you retire it.

Then set the useful life in whole years, between 1 and 40, and pick a method from the dropdown. Press Calculate. If any entry is missing or out of range — for example a salvage value higher than the cost — the calculator tells you exactly what to fix instead of guessing.

Straight-Line Depreciation

Straight-line is the simplest method: the same expense every year. It suits assets that lose value evenly, like office furniture or a warehouse rack that ages at a steady pace.

The formula is:

Annual depreciation = (Cost − Salvage value) ÷ Useful life

A $25,000 machine with a $2,500 salvage value and a 5-year life gives ($25,000 − $2,500) ÷ 5 = $4,500 per year. The calculator also divides that by 12 to give the monthly figure, which is handy for monthly financial statements.

Double-Declining Balance Depreciation

Double-declining balance is an accelerated method: it charges twice the straight-line rate against the current book value each year. Businesses like it when an asset loses most of its value early, such as a company car.

The formula is:

Year 1 depreciation = Cost × (2 ÷ Useful life)

On the same $25,000 machine with a 5-year life, year one is $25,000 × (2 ÷ 5) = $10,000 — more than double the straight-line amount. The charge shrinks each year as the book value falls.

Sum-of-the-Years’ Digits Depreciation

Sum-of-the-years’ digits is another accelerated method, milder than double-declining balance. It multiplies the depreciable amount by a fraction that shrinks each year: the remaining life over the sum of all the years’ digits.

The formula is:

Year 1 depreciation = Depreciable amount × Life ÷ (Life × (Life + 1) ÷ 2)

For a 5-year life the denominator is 5 × 6 ÷ 2 = 15, so year one takes 5/15 of the depreciable amount. That gives a gentler front-loading than double-declining balance.

What Counts as a Depreciable Asset?

Not everything you buy can be depreciated. The asset must have a useful life longer than one year, wear out or become obsolete, and be used in a business or income-producing activity. Machines, vehicles, buildings, and office equipment qualify.

Land never depreciates, and personal-use items like your family car generally do not either. Inventory and investments follow different rules. When in doubt, ask an accountant whether your purchase belongs on the depreciation schedule at all.

How Salvage Value Affects Your Numbers

Salvage value is the finish line: depreciation only spreads the cost down to that floor. A higher salvage value means a smaller depreciable amount and lower yearly charges.

Set it to zero and you depreciate the full cost, which is common for equipment expected to be worthless at retirement. Be realistic here — an inflated salvage value understates expenses, while a pessimistic one front-loads them. The calculator rejects any salvage value at or above the cost, since that would make the depreciable amount negative.

Choosing a Useful Life That Holds Up

Useful life is your estimate of how long the asset will serve you, not how long it physically survives. A laptop might run for eight years but be useful for only four before software outgrows it.

Tax authorities publish standard lives for common asset classes, and lenders often have their own expectations. Picking a life that is too long spreads the cost thin and flatters early profits; too short and you overstate early expenses. The calculator accepts 1 to 40 years, which covers everything from a short-lived tool to a commercial building fit-out.

Worked Example: Straight-Line on a $25,000 Machine

First: list the inputs. Cost is $25,000, salvage value is $2,500, and the useful life is 5 years.

The depreciable amount is $25,000 − $2,500 = $22,500.

Then: divide by the 5-year life. $22,500 ÷ 5 = $4,500 per year.

Monthly, that is $4,500 ÷ 12 = $375. After year one the book value is $25,000 − $4,500 = $20,500. The calculator shows exactly these figures when you select the straight-line method.

Worked Example: Double-Declining Balance on a Delivery Van

First: a van costs $32,000, has a $4,000 salvage value, and a 4-year useful life.

The rate is 2 ÷ 4 = 50% of book value per year.

Then: year-one depreciation is $32,000 × 50% = $16,000 — half the van’s cost in a single year.

The book value after year one drops to $16,000. Notice the salvage value does not enter the year-one math here; it only matters as the floor the balance must never cross in later years.

Worked Example: Sum-of-the-Years’ Digits on Office Equipment

First: equipment costs $18,000 with zero salvage value and a 4-year life. The depreciable amount is the full $18,000.

The denominator is 4 × 5 ÷ 2 = 10, so year one takes 4/10 of the amount.

Then: $18,000 × 4/10 = $7,200 for year one, with a monthly equivalent of $600.

Year two would take 3/10, or $5,400, and so on down to 1/10. The fractions always add to one, so the full $18,000 is spread across the four years.

Depreciation vs. Amortization vs. Depletion

These three words describe the same idea applied to different assets. Depreciation covers tangible assets like machines and vehicles. Amortization covers intangible assets like patents and software licenses.

Depletion covers natural resources — the timber, oil, or minerals pulled out of the ground. The math is similar, but the asset class changes the rules and the tax treatment. For a calculator like this one, depreciation is the term that applies to the physical assets most businesses buy.

Common Depreciation Mistakes

The most common mistake is depreciating the full cost while ignoring a real salvage value, which overstates the expense. The opposite error — guessing a salvage value near the cost — understates it and leaves a surprise write-off later.

Another classic slip is mixing methods mid-life without a plan; switching from accelerated to straight-line can be legitimate, but doing it casually makes your books inconsistent. Finally, people forget partial years: an asset bought in October usually gets only a few months of depreciation in year one, not the full annual amount.

Where Depreciation Calculations Are Useful

Tax planning is the biggest use: depreciation lowers taxable income, so the method you choose affects how much tax you pay and when. Businesses also use it to price products, because equipment cost has to be recovered through sales.

Buyers and sellers use book value as a starting point in negotiations for used equipment. And anyone preparing financial statements needs depreciation to match expenses to the periods when the asset actually produced revenue.

How to Interpret Your Result Correctly

Read the first-year figure as an accounting allocation, not as cash leaving the business — the cash left when you bought the asset. The monthly number helps you budget the cost into monthly profit and loss.

The book value is what the asset is carried at on your balance sheet, not necessarily what you could sell it for. Market prices and book values drift apart, especially under accelerated methods, so treat book value as a record-keeping number rather than a price tag.

Worked Example: Comparing All Three Methods Side by Side

First: take the same asset for all three — cost $25,000, salvage $2,500, life 5 years, depreciable amount $22,500.

Straight-line gives $4,500 in year one. Double-declining balance gives $25,000 × (2 ÷ 5) = $10,000. Sum-of-the-years’ digits gives $22,500 × 5/15 = $7,500.

Then: the ranking is clear — double-declining balance front-loads the most, sum-of-the-years’ digits sits in the middle, and straight-line spreads evenly.

Over the full five years all three methods depreciate the same $22,500 total. The only difference is timing, which is exactly why tax planners care so much about the choice.

Frequently Asked Questions

1. What is the depreciable amount?

It is the cost of the asset minus its salvage value. This is the total that gets spread across the useful life, and the calculator shows it as one of the result rows.

2. Which depreciation method should I choose?

Use straight-line for assets that wear evenly, like furniture. Use double-declining balance or sum-of-the-years’ digits for assets that lose value fast early on, like vehicles or computers. Tax rules in your country may limit your options.

3. Can the salvage value be zero?

Yes. Zero means you expect the asset to be worthless at the end of its life, and the calculator will depreciate the full cost. This is common for specialized equipment with no resale market.

4. What is book value?

Book value is the original cost minus all depreciation charged so far. The calculator shows the book value after year one; it is an accounting figure, not a guaranteed selling price.

5. Does depreciation affect cash flow?

Not directly. Depreciation is a non-cash expense — the cash was spent when the asset was purchased. It does reduce taxable income, which can lower the tax you pay and therefore preserve cash.

6. Why does double-declining balance ignore salvage value in year one?

Because the method applies its rate to the full book value at the start. The salvage value acts as a floor: in later years you stop depreciating once the book value would drop below it.

7. What happens if I sell the asset before it is fully depreciated?

You compare the sale price to the book value at the time of sale. Selling above book value usually creates a taxable gain; selling below creates a loss. Both are measured against the depreciated figure, not the original cost.

8. Can I change the useful life later?

Yes, if your estimate genuinely changes — for example a machine lasts longer than expected. Accountants treat this as a change in estimate and adjust future depreciation, not past years.

9. Is land depreciated?

No. Land does not wear out, so it is never depreciated. Buildings and improvements on the land are depreciated separately from the land itself.

10. What is the 2 in double-declining balance?

It means the rate is twice the straight-line rate. A 5-year asset has a straight-line rate of 20%, so double-declining balance charges 40% of the declining book value each year.

11. How is sum-of-the-years’ digits different from double-declining?

Both are accelerated, but sum-of-the-years’ digits uses a shrinking fraction of the depreciable amount while double-declining applies a fixed rate to a shrinking balance. Sum-of-the-years’ digits front-loads less aggressively in year one.

12. Does the calculator handle partial first years?

No. It assumes a full year of depreciation in year one. If you bought the asset mid-year, prorate the first-year figure by the number of months you actually used it.

13. Why is my monthly figure not exactly the annual divided by 12 in real accounting?

In real accounting the monthly figure often is exactly annual ÷ 12. Small differences appear when accountants round each month or apply half-year conventions, which this calculator keeps simple by dividing evenly.

14. Can I depreciate a used asset I just bought?

Yes. Depreciation starts from your purchase cost and your own estimate of remaining life and salvage value, not the original owner’s numbers. You begin the schedule on the date you place it in service.

15. Is this calculator’s result valid for my tax return?

It is a correct application of the standard formulas, but tax law adds conventions, limits, and bonus rules that vary by country and year. Treat the result as a planning estimate and confirm the filing with a tax professional.