The 36-Year Mortgage: Smart Shortcut or Future Regret?

6 min read · June 2026

Five years ago, mortgages longer than 25 years were rare. Now lenders routinely offer 35-year and even 40-year terms. The math is obvious: spread the repayment over more years, and the monthly payment drops. If you can't afford the house on a 25-year mortgage, a 35-year term suddenly makes it possible.

But that lower monthly payment is hiding two uncomfortable facts: how old you'll be when it's paid off, and how much total interest you'll hand to the bank.

You'll be paying this mortgage into retirement

Let's use a real example. You're 32, you get a 35-year mortgage. That's paid off when you're 67. Which is after state pension age — meaning you're still paying a mortgage on a house you no longer own (because you've retired or you're about to).

For some people, that's fine. They'll downsize or move, and the house sale pays off the remaining mortgage. But plenty of people don't think that far ahead. They imagine a paid-off house and a pension. Instead, they get a pension statement and a mortgage bill on the same day of the month.

The calculator shows you your age at the point the mortgage ends. Look at that number. Seriously look at it. Does that feel like the right time to still be paying for a house?

The total interest is staggering

Let's compare the cost of a £300,000 mortgage at current rates (roughly 5.5%):

• 25-year term: Monthly payment around £1,700. Total interest paid: £210,000.
• 35-year term: Monthly payment around £1,360. Total interest paid: £273,000.
• 40-year term: Monthly payment around £1,215. Total interest paid: £281,000.

That £340 per month saving (25 to 35 years) costs you an extra £63,000 in interest. The bank wins. You win on cash flow month-to-month, but you lose by tens of thousands of pounds overall.

Why lenders love long mortgages (and why that matters)

Banks offer long mortgages because they earn more interest. They also lower the risk that you'll default — if you can only afford the house on a 35-year term, a shorter term would have meant you couldn't afford it at all, and wouldn't have been a customer. Long mortgages expanded the market to people who technically can't afford the houses they're buying, but the lender's happy because the interest is enormous.

This isn't a moral argument about banks. It's just: if you're stretching to a 35 or 40-year term, you should know exactly what you're paying for the stretch.

When long mortgages actually make sense

There are a few scenarios where a longer term is genuinely sensible:

• You have a clear plan to pay it off faster. If you're taking a 35-year term at age 32 with the genuine intention to pay extra and clear it by 50, that's different. (But be honest: do you have the discipline?)
• Your income is likely to increase significantly. If you're starting a career that'll see big salary growth in the next five years, stretching now and then shortening the term later is reasonable.
• You have substantial other investments or pensions. If you're confident your pension and ISAs will be enough, a longer mortgage is just about cash flow.
• You're buying young and expect to sell before it's paid off. If you're 25, buying your first house, and you know you'll move or upgrade in ten years anyway, the term length doesn't matter — you'll sell before it matures.

If none of these apply, a longer term is just expensive financial stretching.

The real conversation: can you afford this house?

Long mortgage terms are often offered as the solution when the answer to "can you afford this house?" is "no, but here's a way to make the numbers work." That's not solving the problem — it's hiding it.

The harder but more honest question is: should you buy a cheaper house now and upgrade later? Or should you save a bigger deposit first? Or should you wait two years for your income to grow?

Any of those might be better than locking yourself into thirty-five years of mortgage payments.