Mortgage overpayment advice

I have a property and two different mortgages (one was ported over from our previous house). The mortgages are:

£34k remaining, interest 3.25% (always 1% above base rate, due to end 2031). Pay roughly £357 per month; interest added roughly £95.
£62k remaining, interest 2.74% (10-year fix, the term ends in 2028; when we took on this it was expected that we would have it paid off by 2045). Pay roughly £386 per month; interest added roughly £140.

We've been overpaying by £300 against the 2.74% one for a few years now, however since the interest rate increases the other one is now at a higher rate.

My question is which am I better off overpaying? The one with higher interest but smaller left to pay or the smaller interest one but most left to pay?

My bank is unable to give us any projections against the £62k 2.74% fix as they say that they only recalculate at the end of the fixed term, and I'm waiting to get the projections against the £34k one. I've also asked them the same question but they are unable to offer me any advice so directed me to a financial advisor.



  • Always the higher interest mortgage, plus as it's the smallest balance once that's cleared you can throw the £357 at the other part.

    I had the same with my mortgage being in two parts, until this summer, albeit at my latest fix the interest rate on the both was the same. Now that's gone I have some additional funds to save/eventually overpay.
    Solo Buyer & MFW
    Start date: January 2016
    At it's highest: -£237,000
    Current Balance:  -£73,754 (March '23)
    2021 OP total: £6,000
    2022 OP total: £10,535

  • Yup the one with the highest interest rate, in some cases different banks might calculate the interest you owe differently (daily/monthly etc) but given the difference in rates that is unlikely to make a substantial difference in your case.

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