Product: depreciation engine
Every method, every convention, every book. Recalculated the moment anything changes.
The calculation is the product. This page is the inventory of what it handles, so that you can check it against your own register before you load a single asset.
Books
Each asset carries four books. A book is a complete set of method, life, convention, salvage, first-year elections and prior depreciation. Changing one book never touches another.
| Book | Purpose | Typical settings |
|---|---|---|
| Book | GAAP financial statements | Straight line over useful life, salvage value, monthly convention |
| Federal | Form 4562 and the federal return | MACRS GDS, half-year or mid-quarter, Section 179, bonus depreciation |
| State | State returns in states that decouple from federal rules | MACRS without bonus, state Section 179 limit, ADS where required |
| AMT | Alternative minimum tax | 150% declining balance or ADS straight line, per class |
Methods and conventions
| Method | Where it is used | Notes |
|---|---|---|
| MACRS GDS 200% declining balance | 3, 5, 7 and 10-year property | Switches to straight line in the optimal year; IRS percentage tables or formula |
| MACRS GDS 150% declining balance | 15 and 20-year property, farm property | |
| MACRS straight line, mid-month | 27.5-year residential, 39-year nonresidential, qualified improvement property at 15 years | Mid-month convention on acquisition and disposal |
| MACRS ADS | Elected or required alternative depreciation system | Straight line over ADS class life |
| ACRS | Property placed in service 1981 to 1986 | Kept for registers with long-lived assets |
| Straight line | Book, state and internal reporting | Salvage value, any life in months |
| Declining balance, 125% to 200%, with or without switch | Book and internal | |
| Sum of the years' digits | Book | |
| Units of production | Machinery, vehicles, extraction | Hours, units, miles from meter readings |
| User-defined tables | Any book | Annual percentages you enter |
| No depreciation | Land, art, construction in progress | Tracked with cost and location; excluded from expense |
| Conventions: half-year, mid-quarter (with the automatic 40% test across the year's additions), mid-month, full month, next month, actual days. | ||
First-year elections and limits
Section 179
Per-asset election with the annual dollar limit and the investment phase-out applied across the entity. The 2026 limits are loaded; prior years are kept for amended returns. Carryforwards of disallowed amounts are tracked.
Bonus depreciation
Applied by class with elect-out per class per year. The 100% rate for qualified property acquired after 19 January 2025, restored in July 2025, is applied automatically; assets acquired earlier keep the phased rates (40% in 2025, 60% in 2024) they were placed in service under. See the tax-update changelog for what changed and when.
Listed property and luxury autos
Business-use percentage per year, the annual dollar caps for passenger automobiles, and recapture when business use drops to 50% or below.
State decoupling
Each state book has its own bonus and Section 179 treatment. A state that does not conform is a setting, not a manual adjustment, and the federal-to-state difference report shows the addback and the subsequent recovery by year.
Short years and fiscal years
Short tax years, fiscal years, and 4-4-5 calendars are handled in the period definition; the tables are prorated the way the regulations describe.
One asset, four books, on one screen
The federal book selected, with the book-basis projection beside it. Switching tabs never changes the other books.
Overrides, and the record of them
Any calculated figure can be overridden: prior depreciation on a converted asset, a year's expense to match a filed return, a remaining life after an impairment. Every override stores the user, the date, the previous value and the reason you type. Overrides appear on the audit trail report and can be reversed.
| Date | User | Asset | Book | Field | Was | Now | Reason |
|---|---|---|---|---|---|---|---|
| 2026-03-04 10:12 | mreyes | 10120 | Federal | Prior depreciation | 52,336.00 | 52,338.00 | Match 2025 return as filed (rounding in prior system) |
| 2026-03-04 10:15 | mreyes | 10412 | Book | Remaining life | 72 mo | 48 mo | Impairment review, board minute 2026-02 |
| 2026-04-01 09:40 | jkim | 10688 | Federal | Bonus election | Elect out | 100% | Confirmed acquisition date 2026-03-02, after 2025-01-19 |
Sample data.
Try it on your own register.
The 14-day trial is the full product. Load a spreadsheet of your assets, run a schedule, and compare it with what you filed. No card is needed.