Mortgage overpayment - repayment or interest only element?

[Emmzo]

We have a split mortgage - part repayment, part interest only. Both parts allow up to 10% overpayment on the capital per year.

The amount of the repayment mortgage is around 4 times the interest only, eg 400k vs 100k. Both are on the same very low interest rate with 2 years left on the term.

I want to make use of the overpayment allowance, but cannot get my head around which one to pay towards, it feels like there would be a reason to go for one over the other, but I can’t work it out! Anyone with a better grasp than me who could help?

Thank you!

I would repay on the interest only first as currently it isn't being reduced. The repayment one is being chipped away slowly to nothing, but you will still owe the full £100k at the end of the term on the interest onl one. If you can overpay by more than the maximum for that, move onto the repayment one.

Pay interest only up to the 10% first.

on interest only I’d look to pay it on the first day each year or monthly not a lump sum ar the end.
Any overpayments on the repayment ensure they are reducing your overall term with the overpayments not you monthly repayment.

but if you can afford a 40k/£50k overpayment every year it’s not clear why you are on interest only?

NEITHER!!!!! ARE YOU MAD?

Sorry for shouting but overpaying an old very low interest rate mortgage is like winning the lottery and burning the ticket.

Put whatever you can in the best paying savings accounts (use your ISA allowances first) and pay off when the current rate ends. If you're on 1 or 2% you can literally benefit up to 4 times as much from the overpayment that way.