Fixed Asset Register & Depreciation Scheduler

The problem this kills

Depreciation is the close task that everyone assumes is automatic and almost nobody trusts. The fixed-asset register lives in a spreadsheet — or three. Every month you re-key the same formulas, add the assets that came in, retire the ones that left, and pray you didn't fat-finger a useful life or forget a partial-period asset that went into service on the 20th. Then you do most of it a second time for tax, because the book method and the tax method don't agree, and the difference is what your deferred-tax schedule is built on.

The failure modes are quiet and expensive. Depreciate a disposed asset and your gain/loss on disposal is wrong. Miss a mid-month in-service date and you over- or under-depreciate the whole first period. Let the roll-forward drift even a few dollars from the GL and your auditor finds it before you do. And the whole thing is one resignation away from being unreproducible, because the logic lives in someone's head and someone's cells.

This is exactly the kind of rules-based, high-stakes calculation a small internal tool does better than a spreadsheet — and you do not need to be a developer to build it.

What you'll build

A simple internal web tool for your close. You import your asset register (asset, cost, in-service date, useful life, method, salvage) and the period's additions and disposals. The tool computes, for each asset, this period's depreciation — under both your book method and your tax method — then rolls forward accumulated depreciation and net book value. It handles partial-period assets (something placed in service mid-month) and disposals (stop depreciating, compute the gain or loss), supports straight-line and the common accelerated methods, and flags anything it can't cleanly compute.

The accountant reviews the proposed depreciation on one screen — by asset and by GL account — edits or excludes anything that looks off, and clicks Approve. Only then does the tool produce the GL-ready depreciation journal, a roll-forward (beginning balance + additions − disposals + depreciation = ending balance) that ties to the GL, and a book-vs-tax schedule showing the difference that feeds your deferred tax.

What's inside the Implementation Plan

The plan is a single file you paste into an AI coding agent. It opens by interviewing you about your business — what your register looks like, which depreciation methods and conventions you use, how you handle partial periods and disposals, your book-vs-tax differences, your GL account mapping, and your nastiest edge cases — and then tailors the data model, the depreciation engine, and every later step to your answers. This is a build shaped around your fixed assets, not a generic template.

From there it walks the agent through the database schema, the register and additions/disposals imports with their duplicate guards, the depreciation calculation engine (book and tax), the accountant's review-and-approve screen, and the export of the journal, the roll-forward, and the book-vs-tax schedule. Every step ends with a ready-to-copy prompt. Because the whole thing runs on CSV in and GL-ready CSV out, you can build and use it this weekend even if you have no direct connection to your accounting system.

The governance it includes (this is the point)

This touches the general ledger, so it is built like it matters: login so only your finance team can use it, row-level security so you only ever see your own entity's assets, and a complete audit trail of every import, edit, approval, and export — who did what, and when. Nothing posts automatically: the depreciation run is a draft until the accountant approves it, and approval is the hard human-in-the-loop gate before anything becomes a journal entry. Duplicate guards on asset + period mean the same asset can't be depreciated twice in the same month and the same run can't be booked twice.

Who it's for

Staff accountants and controllers who own the fixed-asset register and book depreciation every period, and who want the calculation to be fast, defensible, and identical every month. If you can explain how you decide each asset's depreciation, you can build this.

You've got this — open the plan, paste the first prompt, and let it interview you about your register.