The unit you quote in changes who calls you, what they expect, and how easy it is to compare you against anyone else.
An hourly rate matches what the work actually costs you, and it protects you when a job turns out worse than described. Its weakness is the customer's side: they cannot tell what they will pay until it is over, which is exactly the uncertainty that makes people keep shopping.
It also invites the wrong question. When the meter is the product, customers start watching the clock instead of the result.
Per square metre gives the customer a number they can work out themselves before calling, which is a real advantage in a trade where most enquiries never turn into a call at all.
The risk moves to you. If your throughput assumption is wrong, or the flat is far worse than described, you absorb it. Firms that price by area and never measure their real coverage per hour are running at an unknown margin.
You need one number: how many square metres one cleaner covers in an hour at your standard. Divide your hourly rate by it and you have your area rate; multiply an area rate by it and you have the equivalent hourly.
Measure it rather than assume it, and measure it per service — a deep clean and a maintenance clean are not the same job at a different price, they are different throughputs.
Your competitors did not all pick your unit. In a typical local market you will find hourly rates, area rates, fixed prices per flat and size tiers on the same street.
Without conversion, a price comparison is just a list of unrelated numbers that happen to have currency signs. With it, you can finally answer whether you are above or below the people you actually lose work to.
Everything above is a job you can do by hand. It is also the job that quietly never happens twice. Competitor price monitoring for service businesses explains how the same reading works when something else keeps doing it.
A practical way to set cleaning prices: work out your cost floor, read what the local market publishes, and decide where between the two you want to sit.
Where service firms actually publish their prices, how to read a price list that hides behind a quote form, and what to record so the comparison is still useful next season.