Depreciation Calculator by Percentage

International Percentage-Based Depreciation Standards

Outside the United States, fixed-rate percentage methods are the norm rather than the exception. In the United Kingdom, HMRC's Capital Allowances system uses Writing Down Allowances (WDAs): the main pool rate is 18% of the pool's declining balance per year, while the special rate pool (integral features of buildings, long-life assets) uses 6%. There is no equivalent of MACRS asset classes—instead, most plant and machinery goes into one of two pools, and the rates apply automatically.

Australia uses a Diminishing Value (DV) rate equal to 200% ÷ asset life, or a Prime Cost (PC) rate of 100% ÷ asset life. A laptop with a 3-year effective life uses a DV rate of 66.67% applied to the declining balance, resulting in depreciation of roughly $3,333, $1,111, and $370 on a $5,000 asset over three years— very front-loaded compared to straight-line. Canada employs Capital Cost Allowance (CCA) classes with prescribed rates, including Class 10 (30% DV for most vehicles) and Class 50 (55% DV for computers), and applies the half-year rule in the acquisition year.

How Custom Percentage Rates Work in This Calculator

This calculator applies your chosen percentage to either the original cost(producing equal annual charges, equivalent to straight-line) or the remaining book value (producing a declining balance schedule). The two produce radically different results. A 20% rate on a $10,000 asset:

• Fixed-base (original cost): $2,000/year for 5 years, book value reaches zero at end of Year 5.
• Declining balance: $2,000 in Year 1, $1,600 in Year 2, $1,280 in Year 3, and so on—the asset never mathematically reaches zero, so most systems switch to straight-line when it becomes more beneficial.

Matching the right base to your jurisdiction's rules is essential. UK WDAs and Australian DV always use the declining balance base; straight-line international GAAP depreciation uses the fixed base.

Prescribed Rates for Common Non-MACRS Asset Categories

Even within the US, certain industries use percentage-based methods outside MACRS. Regulated utilities apply straight-line percentage rates prescribed by the Federal Energy Regulatory Commission (FERC), which can differ from IRS recovery periods. Oil and gas companies may deduct intangible drilling costs using a cost-depletion percentage. Real estate investment trusts tracking individual properties sometimes apply custom declining-balance rates for internal performance reporting, then convert to MACRS for tax. Understanding the relationship between your custom percentage rate and the underlying method (fixed vs. declining) ensures the schedule you generate here matches your actual accounting policy.