Mortgage payments

[sponsmith]

I have a �102,000 mortgage with 23 years left to pay.
My mortgage tracks at 1% above the BOE base rate for the life of the loan. I repay round �600 a month. If i overpayed by �100 a month how long would it knock of the repayment period, assuming the base rate stayed the same?

[Gnu]

I'd estimate that it would take 18 years to pay, so it would knock 5 years off. It would also save about �17 000 in interest payments.