Interest rate
A higher rate raises both costs
5% · 30 years£1,342 / month6% · 30 years£1,499 / month
On a £250,000 mortgage, one percentage point adds £157 a month and £56,456 total interest.
Mortgage term
More years lower the monthly payment
25 years · 5%£1,461 / month35 years · 5%£1,262 / month
The longer term saves £200 a month but adds £91,480 total interest.
The useful comparison
Check monthly and lifetime cost together
- RateChanges the cost of every pound still owed.
- TermSpreads repayment across more or fewer months.
- Total interestShows the long-run trade-off hidden by a smaller monthly figure.
Sources
MoneyHelper interest-rate guide · MoneyHelper repayment mortgages