[jimnotgym]

This sounds fine for a contractor sending out one bill per month, but would you recommend it for a larger entity?

I couldn't fit all of the transactions in a given month into Excel for my business. There are more than 1m rows. We are only an SME.

[mellavora]

the problem with being a larger entity is there may be legal requirements around your accounting system.

In many EU countries, if your turnover (total amount of money flowing through your business) is over a certain amount, or if you are incorporated (rather than sole proprietor) you have a legal requirement for double-entry accounting, and in some places a legal requirement to have an external firm do your accounting.

[hedora]

Excel PowerBI would easily handle millions of transactions, but it's arguably a completely different product hidden inside an excel menu.

[jimnotgym]

Yes, but once you are using Power BI you have lost the friendly interface the op described for categorising transactions, ie it is not a simple spreadseet any more.