Guide · 29 August 2026

Six signs your spreadsheet has quietly become a business system

Nobody decides to run their business on a spreadsheet. It starts as a list, someone adds a column, and two years later it is the only record of who owes what. These are the six points at which it has stopped being a document and become software nobody maintains.

One: somebody is the only person who can touch it

There is a person who understands the formulas, and everyone else sends them changes. That is not a spreadsheet any more, it is an application with one developer and no documentation.

The cost is not the time they spend on it. It is the fortnight where they are on holiday and the business runs on guesses.

Two: it has a copy called final, and one called final-2

Version confusion means two people have made different decisions from different numbers on the same day. Software solves this by having one record; a file solves it by hoping.

Three: you check it to find out what needs doing

A record tells you what happened. A system tells you what to do next. When somebody opens the file each morning to work out today's jobs, the file is doing a system's work without a system's safeguards.

Nothing chases, nothing reminds, nothing flags the thing that has sat there for three weeks.

Four: it has started holding personal data

Names, phone numbers, addresses, sometimes more. Once that is in a file that gets emailed around and copied to desktops, you have taken on a data-protection obligation with none of the controls that normally come with it: no access control, no audit trail, no way to delete somebody properly when they ask.

This one is worth acting on ahead of the others, because it is the only one on this list that can turn into a legal problem rather than an efficiency one.

Five: the same information lives in three places

The spreadsheet, the accounting package and somebody's inbox each hold a version of the same customer. Somebody reconciles them, usually on a Friday, usually badly.

That reconciliation is a job nobody was hired to do and nobody is measured on, which is why it keeps happening.

Six: you have stopped adding to it

The clearest sign. When people stop putting things in because it is too fragile, too slow or too likely to break, the record has stopped being trusted, and decisions get made on memory instead.

At that point the spreadsheet is not saving anything. It is a thing you maintain that no longer tells you the truth.

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