THERE'S a bit of me that yearns for the old days when you only had three categories to pick from, upper, middle or working, and we could all be a bit shirty, protective or apologetic over these.

The middle-class could pretend they were really working-class. The upper-middles and middle-uppers could get confused about where they belonged. People like Peter Hitchens could describe themselves as "lower-upper-middle". People like me could be middle-middle-middle.

Others could get on their uppers about daft, but enduring, dividing signals, like whether you call a toilet a loo. But today it's not so simple. Now there are seemingly endless ways of carving us up socio-economically and as consumers. We can, these days, ask ourselves if we are a striver or a shirker. We can, according to Harry Wallop in Consumed: How Shopping Fed The Class System, work out if we belong to the Portland Privateers (too posh to push), the Wood-burning Stovers (Guardian-reading types), the Asda Mums, and various other invented groups. And now, the BBC has got together with university academics to devise the Great British Class Survey, which declares that we all belong to one of seven new categories.

The survey was announced along with a handy class calculator, which asks you to answer questions about income and house value, as well your social circle, hobbies and musical tastes, before telling you where you sit in the 21st-century social strata.

Already this calculator has been deluged. If we ever liked to pretend that we were a society that has moved beyond class, then this fact alone shows that to be a lie. Far too many of us have used the calculator to discover where we are on a scale that climbs from "precariat" (precarious proletariat) to "elite".

Since the calculator was unveiled last week, the comments online have revealed a nation baffled. Male newspaper columnists have been perplexed by the idea that they could possibly be "elite". There are toffs who have fallen on hard times, and are almost charmed by their reclassification as members of the precariat. Those who have been declared "technical middle class" are troubled by the implication they don't get enough culture.

But me, I didn't mind. The calculator tells me that I am "established middle class". No surprise there. I have always, since I was working things out in my rural state school, thought I was middle-class, so the word "established" seems just the natural adjunct to something I had worked out for myself many years ago. Dad had a farm. It went bankrupt and then we didn't have it. But we were still sitting there, reasonably comfortably, right in the middle. The word seems to suit me: middle-sized, middle-income, a little plump around the middle. It says, boringly, little new.

One of the problems with this online calculator is that the results often seem not quite to relate to the emotional and personal sense people have of their own class. This could be because we are all self-deluding fantasists, or it could be that it's just a very blunt instrument.

A friend of mine apparently belongs to the precariat, but only 10 years ago she would have been classed as one of the high-earning elite. Class is something we think of as more enduring and more essential than this blip in time. This friend, with all her cultural capital and experience, is clearly many rungs up the class ladder from me. It would only take one good job offer for her to be back up there again. But now she is drifting, living off her social capital, and there is no way the calculator can cope with this. It is all about the snapshot of the now.

Meanwhile, it turns out my brothers are all emergent service workers, which slightly shocked me and them since that category is just one up from precariat and I thought we were all bumbling along in our own rather similar middle-class ways. The difference seems to be that they, being younger, haven't yet bought property. The emergent service workers, we are told, are a "new, young, urban group who don't have much money but are very social and cultural – they 'live for today'."

Obviously, there is extensive social science backing the original survey, but the BBC's online caclulator has the quality of one of those quizzes that ends by telling you which character from your favourite TV show you are. The temptation is to play with it, to redeal your cards and see if you get a new fortune. Or, alternatively, get a cheap thrill by doing it as some other person you know. Reading the comment threads, it's clear that many people have done exactly this. Everyone is on the fiddle, trying to see which tweak might edge them up or down: if being friends with a lorry driver might make that difference, or if it's listening to hip-hop or owning your own home.

Over the past few days, The Guardian has seemed obsessed by the calculator, carrying numerous articles on the subject. Best of all was a piece by a "technical middle class" member on what characters from The Wire score on the calculator. Needless to say, drug-gang leader Avon Barksdale was one of the elite.

One of the problems is that the names of these categories seem a little like Harry Wallop's groupings, but without the satirical jokey resonance. They tell us what is out there, not why it is there. But "why?" is the real issue.

Perhaps, in the long run, these new categories might help us gain some understanding of our levels of inequality and social immobility. But for now the survey just seems like the latest daft personality quiz. There to be played with, and cheated at. Next time round, I'm being George Osborne. You can be Kate Middleton.