In AEC, Excel is not just a spreadsheet. It has been the project delivery platform.
Cost plans, material trackers, programme-linked cashflows, procurement logs, QA registers: all of it lives in Excel. In many firms, it is the UI layer for bespoke tools, VBA macros hiding databases, pivot tables acting as dashboards, named ranges passing data between systems. Excel is the common language of the industry.
Ben Thompson made a point on Sharp Tech that reframes what is coming: “Excel is the world’s most popular programming environment. Every IF statement, every VLOOKUP, every formula a QS writes to reconcile actuals against budget, that’s a program.” And the shift he is describing is not from Excel to something fancier. It is from humans mediating tools to models mediating tools. When an LLM gives you a calculated answer today, it is not guessing from memory. It opens its own version of Excel, runs the computation deterministically, and returns the result.
But the part that matters most for AEC is this: if you feed the model with consistent information, you get consistent calculations. That was always Excel’s hidden value, not the grid, but the shared formula. One spreadsheet, one formula, everyone’s cost plan calculated the same way. The model does that across every project, every office, every discipline, without anyone manually maintaining the template.
The problem was never Excel. It was the 500 slightly different versions of the spreadsheet, each in a shared drive.
The opportunity is not replacing individual spreadsheets. Excel carries institutional knowledge: the cost breakdown structure a firm has refined across hundreds of projects, the risk allowances a senior estimator has encoded in formulas, the calculation logic that lives in one person’s master template and nowhere else. That knowledge moves at the speed of whoever maintains it, and it stays locked in the file they own.
If the model becomes the intermediary, that stored knowledge becomes the input. Feed it the logic from every spreadsheet that has ever worked, and you get one intelligence that applies the same calculations across every project, every team, every office. The QS, the project controller, and the estimator: all querying the same brain instead of maintaining their own version of the truth.
Not 500 versions of the template. One.