Port + Top up or New Mortgage
We're looking to upsize from our flat to a house. Max purchase price is £546,000, deposit £186,000 and joint income of £91,000. My wife will go back to full-time work iin two years so that will go up to £117,000
I always assumed porting our existing mortgage and taking a top-up was the most logical route to avoid early repayment charges. However, when I compare the two options, the monthly costs look very different:
Option 1: Port + Top-up (£364,000 total):
- Ported mortgage: £186,000 @ 3.84% over 13 years = £1,516/month
- Top-up mortgage: £178,000 @ 4.6% over 25 years = £1,000/month
- Total: £2,516/month
Option 2: New Nationwide mortgage (from their own calculator):
- £364,000 over 25 years = £1,956--£2,190/month
At a like for like borrowing amount, the new mortgage comes out roughly £300-£550/month cheaper. My assumption was that porting would avoid early repayment charges and preserve the lower rate on the existing balance, but the monthly difference is a lot higher,
Am I missing something? I understand there could be early repayment costs if leaving the existing mortgage, so I need to take that into account.
How accurate are those calculators?
Appreciate any feedback.