Appliance Depreciation Calculator (straight-line value by age)

Understanding the appliance depreciation calculator — concept and principle

This calculator estimates the current value of an appliance with straight-line depreciation from its purchase price, purchase date, useful life and salvage value. It shows depreciation so far, per year and per month, the share of value lost, the age, the remaining life and the date it is fully depreciated. Use it for insurance claims, selling a used appliance, rental-property records or deciding whether to repair or replace.

The value falls by the same $120 each year down to the 10% salvage value.

How it is calculated

Yearly depreciation = (price − salvage value) ÷ useful life.
Age = days since purchase ÷ 365.25.
Value now = price − yearly depreciation × age, never below the salvage value.
Monthly depreciation = yearly ÷ 12.

The result changes daily, because age is counted from the purchase date to today.

The principle

Straight-line depreciation assumes an item loses the same amount of value each year until it reaches its salvage value at the end of its useful life. It is the simplest method and is widely used in accounting and for rough valuations. For tax purposes in the US, appliances used in a residential rental have a recovery period of 5 years under the general depreciation system and 9 years under the alternative system, according to IRS Publication 527. Tax depreciation also uses conventions, such as a half-year in the first year, that this simple model leaves out.

Worked example

Default inputs: price $1,200, bought 11 Nov 2023, useful life 9 years, salvage 10% ($120). On the day the page was checked, the age was 1,095 days.

Yearly depreciation = (1,200 − 120) ÷ 9 = $120; monthly = $10.
Age = 1,095 ÷ 365.25 ≈ 2.998 years (shown rounded as 3).
Depreciation so far = 120 × 2.998 ≈ $359.75.
Current value = 1,200 − 359.75 = $840.25, about 30% of value lost.
Remaining life ≈ 6 years; fully depreciated on 10 Nov 2032.

Each point is the calculator re-run with only “Purchase price” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Purchase price	Current value of the appliance
300	$210.06
600	$420.12
900	$630.18
1,200	$840.25
1,500	$1,050.31
1,800	$1,260.37
2,400	$1,680.49

How to read the result

The current value is a book estimate, not a market price. Used appliances often sell for less than their depreciated value, while insurers apply their own tables. If a repair costs more than the current value, replacement is often the better choice, though energy efficiency and reliability also matter.

Common mistakes

Using a useful life that does not match the purpose (tax, insurance, or personal valuation).
Forgetting the salvage value, which makes the value drop to zero.
Expecting tax depreciation to match this straight-line figure; tax rules use conventions and tables.
Using today's price for a new model instead of the original purchase price.

Keep in mind: Tax depreciation follows IRS rules and tables that this simple model does not fully apply. For tax returns, use the IRS publications or a qualified tax professional. This is not tax or financial advice.

Frequently asked questions

How long does an appliance last for depreciation?

It depends on the purpose; for US residential rental property, the IRS recovery period is 5 years (GDS) or 9 years (ADS).

What is salvage value?

The value expected at the end of the useful life, for example scrap or resale value.

Why does the value change every day?

Age is counted in days from the purchase date to today.

Sources: IRS, Publication 527, Residential Rental Property (MACRS recovery periods)

Checked 9 Nov 2026. Straight-line method and recovery periods for appliances, carpets and furniture used in residential rental property (GDS 5 years, ADS 9 years): IRS Publication 527, Residential Rental Property, table “MACRS Recovery Periods for Property Used in Rental Activities”.

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