Cloud vs On-Premises TCO Calculator for Enterprise IT Decision-MakersCase Study

TCO modelling was complex and slow. IT and finance teams built business cases in large spreadsheets with interlinked formulas, where a single broken reference could distort the outcome. Different analysts used different assumptions, so models for similar decisions could not be compared, and reviewing someone else's workbook was time-consuming and error-prone.

Presentation was a second problem. Spreadsheet outputs were difficult to share with executives, impossible to explore interactively during a board discussion, and had to be manually converted into charts and slides. When leadership asked what would happen if a cost assumption changed, analysts had to go away and rework the model, delaying decisions and weakening confidence in the numbers. In some cases, competing versions of the same workbook circulated at once.

PapaSiddhi built an interactive web-based TCO calculator using React on the front end, a Node.js modelling engine and a PostgreSQL database that stores scenarios, assumptions and saved reports. Chart.js powers the interactive financial projection charts, and a PDF generation API produces executive-ready reports that can be circulated ahead of investment meetings.

The calculator supports multi-scenario TCO comparison modelling across cloud, on-premises and hybrid options side by side. Configurable cost parameters and assumptions let each organisation reflect its own hardware, licensing, staffing and consumption figures, while standardised calculation logic ensures every scenario is modelled consistently. Default assumptions give first-time users a sensible starting point, which experienced analysts can then override with organisation-specific figures and document for reviewers.

Sensitivity analysis and what-if scenarios allow users to adjust key variables and immediately see the effect on projected costs, which turns board discussions into live exploration rather than follow-up actions. Scenarios can be saved, shared with colleagues and exported, so finance and IT work from the same model. Every change to an assumption is visible, which makes the model easy to audit and defend when leadership challenges a projection.