Calculator Inputs
This page keeps a single-column layout overall, while the calculator fields use three columns on large screens, two on smaller screens, and one on mobile.
Formula Used
Total Cost = Unit Cost × Quantity
Total Salvage Value = Salvage per Unit × Quantity
Depreciable Base = Total Cost − Total Salvage Value
Annual Depreciation = Depreciable Base ÷ Useful Life
First-Year Depreciation = Annual Depreciation × Proration Factor
Straight-line depreciation spreads the depreciable base evenly across the asset’s useful life. A proration method adjusts only the first year, then the calculator continues annual depreciation until the remaining book value reaches salvage value.
Monthly depreciation is shown for planning purposes as Annual Depreciation ÷ 12.
How to Use This Calculator
- Enter the asset name, category, unit cost, and quantity.
- Provide salvage value per unit and the useful life in years.
- Choose the starting year and first-year proration method.
- Select a currency symbol and preferred decimal precision.
- Click Calculate Depreciation to view the summary, full schedule, and chart.
- Use the export buttons to save results as CSV or PDF.
Example Data Table
| Asset | Category | Unit Cost | Salvage per Unit | Life | Quantity | Proration | Start Year |
|---|---|---|---|---|---|---|---|
| Office Workstation | Equipment | $5,000 | $500 | 5 Years | 1 | Full Year | 2026 |
| Warehouse Scanner | Technology | $2,400 | $200 | 4 Years | 3 | Half Year | 2026 |
| Delivery Van | Vehicle | $28,000 | $4,000 | 6 Years | 1 | 8 Months | 2026 |
Frequently Asked Questions
1. What is straight-line depreciation?
Straight-line depreciation spreads an asset’s depreciable cost evenly over its useful life. Each full year usually records the same expense unless you apply a partial first-year convention.
2. Does salvage value affect depreciation?
Yes. Salvage value reduces the depreciable base. The calculator subtracts total salvage from total asset cost before dividing by useful life.
3. Why can the first year be smaller?
The first year may be smaller when you choose half-year or custom-month proration. That adjusts the initial expense to match a shorter in-service period.
4. Why can the final year be smaller?
A smaller first-year amount often creates a shorter final-year catch-up entry. Rounding differences can also make the last depreciation amount slightly smaller.
5. What does book value mean?
Book value is the asset’s remaining carrying amount after accumulated depreciation. It starts at cost and declines until it reaches the estimated salvage value.
6. Can I calculate multiple units together?
Yes. Enter the quantity and the calculator multiplies cost and salvage value across all units before computing the annual depreciation schedule.
7. Is straight-line depreciation always used for taxes?
Not always. Financial reporting may use straight-line, but tax rules can require different methods, rates, or conventions depending on jurisdiction and asset class.
8. Can I export the results?
Yes. When results are available, use the CSV button for spreadsheet analysis or the PDF button for a clean shareable report.