loan calculation maths question

[Deleted User]

hi.
as I only get annual statements from the student loans people, i want to be able to predict the amount of interest due.

for example when the APR was til recently 2.4% (a daily rate of .0065%), in feb 07, the interest owed was £8.32 bringing the balance to 4578.39. What formula brings me from £4570.07 to £8.32?

i did this calculation:
8.32 / 4570.07 = 1.820541042041e-03
0.0018205410420410 * 100 = 0.182054104204
0.182054104204 / .0065 = 28.008323723692

but if i didnt know it was 8.32, how could i derive it?

ta.

scottishlass

I guess it would roughly be

New value = Previous value * (1 + interest)^n

Where the interest is worked out by apr/the number of interest periods

So your Feb 07 seems to be worked out by

4570.07 * ( 1 + (0.024/365))^28 = 4578.39 (approx)

Hope that helps

[Deleted User]

thanks for that.

though why do you think there is a 10p discrepancy ie my result of the calculation was 4578.49 vs the 4578.39?