25, 30 or 35-year mortgage: which is better?
The short answer: a longer term lowers your monthly payment but costs much more in total. On a £200,000 mortgage at 6%, going from 25 to 35 years saves about £148 a month but adds around £92,379 in interest. A common middle path is a longer term for safety, with regular overpayments to cut it down.
£200,000 at 6% over 25, 30 and 35 years
| Term | Monthly payment | Total interest | Still owed after 5 years |
|---|---|---|---|
| 25 years | £1,289 | £186,581 | £179,864 |
| 30 years | £1,199 | £231,676 | £186,109 |
| 35 years | £1,140 | £278,959 | £190,206 |
The monthly saving shrinks with each extra five years: 25 to 30 saves £90 a month, but 30 to 35 saves only £59. The extra interest keeps growing, though.
The same loan at 4.5%
| Term | Monthly payment | Total interest |
|---|---|---|
| 25 years | £1,112 | £133,499 |
| 30 years | £1,013 | £164,813 |
| 35 years | £947 | £197,536 |
Lower rates shrink the gap, but a longer term still costs tens of thousands more. Rates will change many times over the life of a mortgage, so treat these as a guide, not a forecast.
Why the balance falls so slowly on a long term
Early payments are mostly interest. After 5 years on a 35-year term you still owe £190,206, against £179,864 on a 25-year term. That matters when you remortgage: owing less means a lower loan to value, which often gets you a better rate.
When a longer term makes sense
- You need it to pass affordability. A lower monthly payment can be the difference between getting the mortgage or not. See how much you can borrow on your salary.
- You want breathing room. A lower required payment protects you if your income drops, as long as you overpay when you can.
- You have dearer debts. Paying off a car loan or credit card first and then shortening the term later can save more overall.
When a shorter term makes sense
- You can comfortably afford the higher payment, even if rates rise.
- You want to be mortgage-free before retiring. See mortgages after 50.
- You would not overpay on a longer term in practice.
The middle path: long term, then overpay
Take 35 years, but pay what a 25-year mortgage would cost, about £1,289 a month. You get close to the 25-year result, but can drop back to £1,140 if money gets tight. Most lenders let you overpay up to 10% of the balance a year without a charge during a fixed deal. See paying off a mortgage early and overpaying or saving.
Age limits
Most lenders want the mortgage repaid by 70 or 75, or by your planned retirement age. At 40, that can cap your term at 30 to 35 years. Some lenders go further if you can show income in retirement.
25 against 35 years for other loan sizes
| Loan | 25 years | 35 years | Monthly saving | Extra interest over 35 years |
|---|---|---|---|---|
| £150,000 | £966 | £855 | £111 | £69,284 |
| £250,000 | £1,611 | £1,425 | £185 | £115,473 |
| £300,000 | £1,933 | £1,711 | £222 | £138,568 |
At 6%, every extra £1 a month you save by going from 25 to 35 years costs roughly £50 to £55 in extra interest over the life of the loan.
How the term changes what you can borrow
If you can afford £1,200 a month, at 6% that pays off about £186,248 over 25 years, or £210,456 over 35 years. That is why first-time buyers often stretch the term: it can lift the loan by tens of thousands. Lenders still cap borrowing at around 4.5 times income, so a longer term only helps if the monthly affordability test is what is holding you back.
The negative equity risk
Because a long mortgage is repaid slowly, a fall in house prices in the early years can leave you owing more than your home is worth. That makes moving or remortgaging harder, as you may be stuck on your lender's standard variable rate. A bigger deposit or a shorter term builds a buffer faster.
Changing your term later
- Shortening: easiest when you remortgage at the end of a fixed deal. Expect an affordability check for the higher payment.
- Lengthening: if payments become too high, many lenders will extend your term, sometimes temporarily with the option to switch back within a set time. It lowers your payment but adds interest.
- Overpaying instead: keeps your options open with no new application. Check your deal's overpayment limit.
Questions to ask yourself
- Could I still pay if the rate went up by 2 to 3 percentage points when my fix ends?
- When do I want to be mortgage-free, and how old will I be at the end of the term?
- Will I really overpay, or will the spare money get spent?
- Do I have savings or dearer debts that should come first?
This is general information, not mortgage advice. Figures assume a repayment mortgage with the rate fixed for the full term, which is unlikely in practice.
Sources
Common questions
Is a 35-year mortgage a bad idea?
Not always. It lowers your monthly payment, which can make buying possible. But you pay much more interest, so it works best if you plan to overpay or shorten the term later.
How much more interest is a 35-year mortgage than 25?
On £200,000 at 6%, about £92,379 more over the full term, if the rate stayed the same.
Can I change my mortgage term later?
Yes. You can usually shorten or lengthen the term when you remortgage, and often in between by asking your lender. Shortening means passing an affordability check again.
Does a longer term help me borrow more?
It can. Lenders test whether you can afford the monthly payment, so a lower payment over a longer term may pass where a shorter term would not.
What is the longest mortgage term in the UK?
Many lenders offer up to 35 or 40 years. Most also want the mortgage paid off by the time you are 70 to 75, so the longest term you can get depends on your age.
Can I shorten my mortgage term later?
Yes, usually when you remortgage or by asking your lender. You will need to pass an affordability check for the higher payment.
Can I extend my mortgage term if I am struggling?
Many lenders will lengthen your term to lower payments, sometimes for a set period with the option to switch back. It costs more in interest, so treat it as a short-term fix.