I still think that the calculator would give you a rough idea of costs. It maybe set up for a family of four but other than the food bill nothing is automatically factored in that would skew it too much - it's only a rough guide after all. A family of four might spend more on a food shop but may well spend less on eating out and socialising. Likewise more spent, proportionally, on kids clothes less on the parents clothes (that's certainly how it works put here). We just used it to work out the minimum wage we would need to make moving viable - set everything to moderate and then had a think ourselves about how much above the figure quoted would be comfortable and compared that to expect wages.
Hope that makes sense. There are single people on here who have made the move so sone may come out of the woodwork to help you a bit more