When should a business replace Excel with custom software?

Every business we work with has a spreadsheet doing a job it was never designed for. It started as a list. Then someone added a status column, then a second sheet for last year, then a macro nobody understands written by an employee who left in 2021.

It usually still works. That is the difficult part — the case for replacing it is rarely urgent, and the cost of replacing it is always specific.

The four signals

We look for four things. One on its own is not a case for custom software. Three together usually is.

Concurrency

More than one person needs to edit it at the same time, and you have started asking whether anyone is in the file.

Audit

Somebody needs to know who changed a number and when — for a regulator, a client, or an argument.

Volume

It has passed the point where a mistake is caught by someone noticing. Errors now surface as customer complaints.

Rules

The logic has outgrown formulas. There are conditions inside conditions, and only one person can safely change them.

What it costs to wait

The cost of keeping the spreadsheet is real but diffuse: an hour a week reconciling, a monthly report nobody fully trusts, one person who cannot take annual leave without the process stalling.

Diffuse costs lose to specific ones, which is why the spreadsheet usually wins the budget argument for another year. The exercise worth doing is putting a number on it. Four hours a week of senior time is roughly $18,000 a year — more than the annual run cost of most systems we build.

When to keep the spreadsheet

If the process is still changing shape every quarter, keep it. A spreadsheet is the cheapest way to iterate on a process nobody has settled yet, and software built on an unsettled process is software you will pay to change.

If only one person uses it, keep it. If it is a calculation rather than a workflow, keep it — Excel is genuinely excellent at calculations.

The trigger is not complexity. It is when the spreadsheet stops being a tool one person uses and becomes a process several people depend on.

Recognise your spreadsheet in this?

Send us a screenshot of it. We will tell you honestly whether it is time.

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