TCO Break-Even Model for Mobile LLM Inference — Reproducibility Workbook and Data

This repository contains the supplementary reproducibility package for the manuscript "A Total Cost of Ownership Model for Cloud API versus On-Device Large Language Model Inference on Mobile Devices: A Break-Even Analysis." The core artifact is a Microsoft Excel workbook implementing the closed-form Total Cost of Ownership (TCO) model described in the paper as native spreadsheet formulas (516 formulas across nine sheets). It reproduces every quantitative result in the manuscript, including the baseline break-even query volume, the per-model-tier and per-user-profile analyses, the two-way model-size × cloud-price heatmap, the one-way (tornado) sensitivity analysis, and the cost-composition breakdown at break-even. Workbook sheets: Parameters, Derived, Scenario_Sweep, Model_Tiers, User_Profiles, Sensitivity, Heatmap, Cost_Breakdown, and References. All input parameters are traceable to peer-reviewed measurement studies or public provider pricing pages; provider-pricing sources were accessed on 26 July 2026 and are treated as representative tier values rather than stable long-term rates. To reproduce a result, open the workbook, adjust the values on the Parameters sheet, and the dependent sheets recalculate automatically. No proprietary data or personal data are included. The workbook is self-contained and requires only a spreadsheet application supporting standard formulas (Microsoft Excel 2016 or later, or LibreOffice Calc).