The business runs on spreadsheets one person understands

How a spreadsheet becomes a system

Nobody decides to run a business on a spreadsheet. Someone needs to price a job, so they build a quoting sheet. It works, so a tab is added for the schedule, then one for stock, then a macro that produces the paperwork. A few years on, the workbook has dozens of tabs, lookups that reach into other files, and a colour code only its author can read.

It is now a system in all but name, without the protections a system would have. Anyone can change anything, nothing records the change, and one careless sort can scramble a sheet without anybody noticing. Copies travel by email. The person who built it cannot take a fortnight off without their phone ringing.

The spreadsheet is a good specification

This is the encouraging part. Much of the effort in a software project goes into working out what the business needs. Here that work has largely been done. The workbook records, in a form that can be read cell by cell, what information you collect, how a price is calculated, what the paperwork looks like and which exceptions exist.

It also shows what people do in practice. A column added at the side and filled with notes is a requirement nobody wrote down. A tab that has been hidden is often a rule that was tried and abandoned. Reading the workbook alongside the person who built it is the quickest way to an accurate scope, which is why this kind of work suits a fixed price.

One caution: a spreadsheet also contains mistakes that have gone unnoticed. Part of the work is deciding, formula by formula, whether the replacement should copy what the sheet does or what it was meant to do.

Your options

Tidy up what you have. Keep the workbook in one shared location such as SharePoint or OneDrive so there is a single copy, lock the cells that hold formulas, add validation to the cells people type into, and write a page explaining how it works. This costs little and may be enough for a small team.

Use a low-code tool. Products such as Microsoft Power Apps or Airtable let a capable member of staff build forms and lists over shared data. They suit simple processes. Complicated pricing or scheduling rules are harder to express in them, and you still rely on whoever built it.

Buy a packaged product. For quoting, job management and stock control there are many products sold by subscription. If one matches how you work, it will usually cost less than anything built for you. The test is how much of your own process you would have to change to fit it.

Have a small web application built. A bespoke application reproduces your rules exactly and adds what the spreadsheet lacks: several users at once, permissions, a record of every change and access from outside the office. It costs more at the start than the other routes. Our spreadsheet to web app package does this at a fixed price.

What we would do first

We would ask for a copy of the workbook and some time with the person who knows it. From that we write down the rules it contains and the screens a replacement would need, and tell you plainly if we think a tidy-up or a packaged product would serve you better.

If a replacement is right, it is built against the spreadsheet: the same inputs go through both, and the answers have to match, or the difference has to be explained, before anyone switches. If the workbook leans heavily on macros, see also our page on Excel and VBA.