Depreciation Calculator

WHAT IT DOES

Depreciation Calculator is a floating calculator panel that computes depreciation for assets using three common methods. Enter the initial cost, salvage value, and useful life, then choose a method — straight-line (even spread), declining balance (accelerated), or sum-of-the-years-digits (weighted). The panel displays a full depreciation schedule showing each year's depreciation and book value.

WHERE IT RUNS

This script runs on any website you visit. It reads only the page you are looking at, never other tabs, bookmarks, or browser data. All data stays in your browser — nothing is sent anywhere.

HOW TO USE

Click the Depreciation Calculator panel button in the BotGentz extension toolbar. The panel appears at the edge of the page. Enter the initial cost of the asset, its salvage value (estimated value at end of life), and the useful life in years. Select a depreciation method from the dropdown. The depreciation schedule updates instantly — showing each year's depreciation and remaining book value. Use "Copy Schedule" to copy the full table to your clipboard. You can save your default method and life settings — they persist across pages.

TECHNICAL MECHANISM

The calculator implements three standard depreciation methods. Straight-line: (cost - salvage) / life, spread evenly each year. Declining balance: a fixed percentage of the remaining book value each year, calculated as 1 - (salvage/cost)^(1/life). Sum-of-the-years-digits: accelerated method where each year's depreciation is (cost - salvage) × (remaining life / sum of years). The schedule is computed client-side in real time using pure JavaScript, with no external dependencies. Each year's depreciation is capped to ensure the book value never drops below salvage value.

THE PANEL

The panel is a floating overlay that you can drag anywhere on the screen by its header. It remembers its position per site so it reappears where you left it. The panel can be collapsed into a small handle to get it out of the way, and snapped to the edge of the page. It can be resized to fit your workflow. Press Escape to close the panel.

PLEASE NOTE

This script requires the free BotGentz extension to run. All data is stored locally in your browser — nothing is transmitted or shared. The panel works on any website. The calculator is for estimation purposes only — actual depreciation may vary based on tax laws, accounting standards, and other factors. Sites change — the script may need updates to match new site structures.