New! Student Finance Calculator 2012

It's a great tool and it throws up a number of anomalies.

For instance have you noticed that middle earners pay far more than high earners (or low earners). I assume high earners pay less over time because they pay their loans off at a faster rate. But doesn't it seem wrong that the highest earners pay less than moderate earners?

Are you able to get me the answer to a few other issues:

1. When two graduates marry and then divorce, does the graduate debt stay with the originator of the debt? I can anticipate real trouble with this if say the woman had given up work to raise kids while the man continued to pay off his loan as he continued to work. The woman would then be left with her student debt burden.

2. What is the effect of cumulative interest in the early years after university when you are likely to be earning less - perhaps continuing academic study with a Masters or PhD programme - or during time away from work - for instance for bringing up children.

3. If, say, one graduate partner in a marriage is not working and the other is, does only one debt get paid down - or is the household income taken into account?

4. If a pair of graduates marry and have combined student loans of say £80,000 (two loans of £40,000) what effect will this have on their ability to get a mortgage? If they were on joint incomes of £50,000pa then they might expect to be able to borrow £200,000 under normal circumstances - but they would already have a working life commitment to repay £80,000; wouldn't lenders deduct that from their potential borrowing amount?

I can see the possibility for the student loan system to have some terrible unintended consequences: eg penalising divorced women; reducing graduates' abilities to buy their own homes; discouraging continued academic pursuit or delaying starting families.

Hope you can help.

Whizzy as it is, both in simplicity and flexibility, I think there is a significant flaw. That is that salary growth for graduates is far from linear in percentage terms, rising much faster over the first 5-10 years of employment than. This podcast from the Office for National Statistics (okay, the forum won't let me post the link so go to youtube and search for 'Graduate earnings over the last decade') provides a pretty good description and shows that the average graduate salary roughly doubles between the ages of 22 and 32, before rising more slowly. The single percentage slider doesn't model this very well and will probably over-restimate repayment time (as people won't realise just how fast salary may rise).

Given the situation isn't simple, it makes a simple solution hard to come by. I'd suggest perhaps separate sliders, one for the first 10 years after graduating and one for the next 20 years. I'd also suggest changing the increments on the salary growth slider to 0.5%. The changes in repayment time from changing this by a single percent can be several years; I seem 5-7 in most circumstances.

Finally, on a more philosophical point, with long term debts such as this, the important thing is not the final cost, but the effect on quality of life. I wouldn't take out a mortgage to save money (total repayment about 2.5 times the original loan), but I have done because it enabled me to improve my quality of life at a reasonable monthly cost. Similarly, the 'cost' of a student loan is more about the reduction in monthly earnings (above a threshold) than the total amount paid back. In that way, it's much more like a tax than a loan.