How do I work out how much my remaining mortgage will be in x years time?

[FrayedKnot]

We took a repayment mortgage out in 2005, at a fixed rate of 5.09%, over 25 years.

Rate is fixed until 2010, after that I can make an assumption on the interest rate.

How do I work out how much it will have been reduced by, by a certain year?

I think that some of the offset mortgage providers have calculators on their websites that allow you to work out how much you would save with an offset - maybe playing about with the figures on something like that would give you a rough idea?

I found this

if anyone else is interested, it gives you the amount outstanding at 5, 10, 15, 20 yrs etc.