Calling Excel a “programming language” sounds wrong like calling a spoon a vehicle. And yet, here we are. In 2026, Microsoft Excel is officially Turing-complete, which means that in theory, it can solve the same kinds of problems as Python, Java, or C++. The only difference? Excel does it inside a grid of innocent looking cells that were never supposed to run the world (but somehow do).
Excel started life as a simple calculator for business people. Add numbers. Make tables. Maybe draw a chart if you were feeling fancy. If you wanted real programming, Microsoft gave you VBA powerful, yes, but hidden away like a dangerous tool only “technical people” should touch. For decades, the spreadsheet itself stayed dumb while the code lived elsewhere.
Then Microsoft quietly changed the rules.
The biggest turning point was the LAMBDA function. Before this, Excel users could use functions but not create them. Now, anyone can write a complex formula once, give it a name, and reuse it like a proper function. Even better (and slightly terrifying), LAMBDA supports recursion, a core computer science concept where a function can call itself. This is the moment Excel crossed from “advanced calculator” into “actual programming environment.”
Another major shift came with dynamic arrays and spilling. Old Excel was strict: one cell, one value, no arguments. Modern Excel lets a single formula return an entire range of values that automatically flows into neighboring cells. Change one input, and the whole sheet updates instantly. At that point, Excel stops behaving like a document and starts acting like a reactive application, basically a low-code web app that runs on accountants.
So why does the entire world rely on Excel? Simple: it meets people where they are. There are over 1.2 billion Microsoft Office users, and Excel sits right in the middle of that universe. You don’t need to install anything. You don’t need to learn curly braces or semicolons. If you can type 1+1, congratulations you’ve started programming.
Excel’s biggest advantage is visibility. In most programming languages, your data is hidden until you print it or log it. In Excel, the data, logic, and output live in the same place. You see everything as it happens. This makes it incredibly powerful for non-developers, and dangerously powerful for everyone else.
This is why so much of the global economy runs on spreadsheets. Banks, logistics companies, hospitals, and governments all depend on Excel models built by people whose job title is definitely not “software engineer.” An analyst can build a working tool in an afternoon that might take an IT department months. This unofficial ecosystem is often called “shadow IT” and Excel is its king.
Excel is also absurdly portable. An .xlsx file is a full application: data, logic, and interface bundled together. You can email it, copy it, or drop it into a shared folder, and it just works. No deployment. No servers. No permissions meeting that lasts three weeks.
Of course, this power comes with risk. There is no code review for spreadsheets. No unit tests. No warning when someone copy-pastes the wrong cell. History is full of Excel horror stories. A single spreadsheet error helped cause JPMorgan’s $6 billion “London Whale” loss. During COVID-19, the UK lost thousands of test records because they hit the row limit of an old Excel file format. When Excel breaks, it doesn’t crash loudly, it fails quietly, which is much worse.
Still, Excel refuses to die. After more than 40 years, it remains the only tool that lets non-coders build complex, automated systems without ever leaving their desk. It may not look like a programming language, but it behaves like one. And whether engineers like it or not, Excel has become the operating system of the business world.
Messy. Powerful. Slightly terrifying. And absolutely everywhere.
