An offset mortgage can be worth it if you keep a substantial amount in savings and pay higher or additional-rate tax. Your savings reduce the balance you pay mortgage interest on, and because that saving is not interest you earn, there is no tax to pay on it. The catch is that offset rates are often slightly higher, so the benefit on your savings has to outweigh the extra interest on the rest of your mortgage.
Key takeaway: An offset mortgage is a tax-efficient home for savings you want to keep within reach, not an automatic win. The bigger your savings compared with your mortgage, the higher your tax band and the smaller the rate gap, the more likely it is to pay off - and the savings tax rise due in April 2027 tips the maths further in its favour.
[[stats: £500 = Tax-free savings interest a year for higher-rate taxpayers (Source: GOV.UK) | 42% = Higher-rate tax on savings interest from April 2027 (Source: Budget 2025) | 1.7% = Of outstanding UK mortgages had linked savings at the end of 2024 (Source: FCA)]]
How does an offset mortgage work?
An offset mortgage links your mortgage to one or more savings accounts, and sometimes your current account, held with the same lender. Instead of earning interest on that money, your balance is deducted from your mortgage before interest is worked out. Barclays gives a simple example: with a £125,000 mortgage and £25,000 in linked accounts, interest is calculated on £100,000.
Your savings usually earn no interest while they are linked, but you can typically still withdraw them if you need to. You then use the benefit in one of two ways:
- Lower monthly payments - you keep the same term and pay less each month.
- A shorter term - you keep paying the same amount, so more of each payment clears the debt and the mortgage ends sooner.
Coventry Building Society, for example, lets borrowers switch between the two at any time. Not every lender works the same way, so it is worth checking how a particular product applies the offset before you choose it.
Why are offset mortgages popular with higher-rate taxpayers?
Because the interest you save by offsetting is never paid to you, it is not taxed. Interest on ordinary savings is taxed once it goes above your Personal Savings Allowance, and that allowance shrinks as your income rises.
[[table: Tax band (2026/27) | Personal Savings Allowance | Tax on savings interest above it | Tax from 6 April 2027 ;; Basic rate | £1,000 | 20% | 22% ;; Higher rate | £500 | 40% | 42% ;; Additional rate | £0 | 45% | 47%]]
The tax rates on savings income are due to rise by 2 percentage points from 6 April 2027, as announced in Budget 2025. The cash ISA limit is also due to fall to £12,000 a year from April 2027, although savers over the age of 65 will still be able to put up to £20,000 a year into a cash ISA. For many higher earners, that means more savings sitting outside an ISA, with more of the interest taxed.
The effect is that a savings account has to pay a much higher rate to match what an offset could save you. On interest above your allowance, using an illustrative offset rate of 4.5%:
[[table: Tax band | Savings rate needed to match a 4.5% offset (2026/27) | From 6 April 2027 ;; Basic rate | 5.63% | 5.77% ;; Higher rate | 7.50% | 7.76% ;; Additional rate | 8.18% | 8.49%]]
Illustrative figures only, not current market rates. The rate needed is the offset rate divided by one minus your tax rate.
Is an offset mortgage worth it? A worked example
The tax saving is only half the story. Offset mortgages often carry slightly higher rates than standard deals, and you pay that higher rate on the part of your mortgage your savings do not cover, which is usually most of it. So the real question is whether the tax-free saving on your offset savings outweighs the extra interest on the rest of your balance.
Example: Take a £300,000 mortgage. Option one is a standard mortgage at an illustrative 4.25%, with your savings in an easy-access account paying 4%. Option two is an offset mortgage at 4.5%, with the same savings linked to it. Looking at the first year in simplified terms, ignoring capital repayments, the table below shows how much option two saves or costs you.
[[table: Savings linked | Basic-rate taxpayer | Higher-rate taxpayer | Additional-rate taxpayer ;; £50,000 | Costs £300 more (£280 from April 2027) | Saves £100 (£130 from April 2027) | Saves £400 (£440 from April 2027) ;; £100,000 | Saves £350 (£410 from April 2027) | Saves £1,150 (£1,220 from April 2027) | Saves £1,550 (£1,630 from April 2027)]]
In this example, the offset only pulled ahead once savings passed roughly £33,000 for an additional-rate taxpayer, £45,000 for a higher-rate taxpayer and £73,000 for a basic-rate taxpayer. A wider rate gap would push those thresholds up, and a narrower one would bring them down.
Illustrative figures only, not current market rates. The example assumes the Personal Savings Allowance stays at today's levels and ignores capital repayments, product fees and changes in rates over time.
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What are the disadvantages of an offset mortgage?
- Higher rates. Accord Mortgages says the rate on an offset mortgage is likely to be higher than on a non-offset mortgage, and Coventry Building Society says offset rates can be slightly higher than its standard mortgages.
- Less choice. Fewer lenders offer offset than standard mortgages, and MoneyHelper notes you may have limited access to discounted rate deals. First Direct and Hinckley & Rugby Building Society, for example, no longer offer offset mortgages to new customers.
- No interest on your savings. Your linked savings stop earning interest, and if you take money out, the balance you pay interest on goes back up.
- Mostly residential only. Coventry Building Society and Accord Mortgages only offer offset on residential mortgages, not buy-to-let.
None of these rule an offset out, but they are why it suits some borrowers far better than others.
Is it better to offset or overpay your mortgage?
Both reduce the interest you pay, and neither benefit is taxed in the way savings interest is. The difference is access. Overpaying puts your money into the property, while an offset keeps it in your name and within reach.
[[table: | Offset mortgage | Overpaying | Savings account ;; Reduces your mortgage interest | Yes, while savings stay linked | Yes, permanently | No ;; Access to your money | Usually yes, at any time | Not usually, without borrowing more | Yes ;; Tax on the benefit | None, as no interest is earned | None, as no interest is earned | Taxed above your allowance ;; Limits | Depends on the product | Many fixed deals allow around 10% a year without charges | Depends on the account ;; Rate | Often slightly higher than standard deals | Standard mortgage rates | Separate savings rate ;; Tends to suit | People with large savings who want flexibility | People sure they will not need the money back | Smaller balances and emergency funds]]
Neither option is better in every case. If you might need the money for a future purchase, school fees or a tax bill, an offset keeps it available. If you are certain you will not need it, overpaying a standard mortgage could achieve a similar saving. Our overpayment calculator can show what regular overpayments could do to your term.
Who could an offset mortgage suit?
[[accordion: I am self-employed and put money aside for tax|Many self-employed people and company directors hold a large balance for their next tax bill. In an offset account, that money reduces your mortgage interest until the bill is due, without being locked away. ;; I receive a large annual bonus|If a bonus lands once a year and is earmarked for something later, offsetting it in the meantime could reduce your interest while keeping the money available. ;; I keep a large emergency fund|An emergency fund needs to be easy to reach, which is exactly what an offset allows, while still reducing what you pay on your mortgage. ;; I am saving for a planned cost|Money set aside for school fees, a car or home improvements can work against your mortgage until you need it. ;; My family want to help without gifting money|A small number of lenders let relatives link their own savings to your mortgage, which can reduce your interest without the money being given away. Rules on whose savings can be linked vary between lenders, so this is worth checking early.]]
If any of these sound familiar, our guides for self-employed borrowers, limited company directors and bonus and commission income explain how lenders assess your income, and our joint borrower sole proprietor guide covers another way family can help.
Which lenders offer offset mortgages?
Fewer than you might think. FCA data shows the share of outstanding UK mortgages with linked savings accounts fell from 2.9% at the end of 2020 to 1.7% at the end of 2024. Lenders currently showing offset mortgages on their own websites include:
[[lenders: Barclays | Links your current and savings account balances to your mortgage ;; Coventry Building Society | Residential only, with one linked offset savings account. Choose lower payments or a shorter term and switch at any time ;; Accord Mortgages | Residential offset products that can be linked to up to three savings accounts]]
Correct as at 13 October 2026. Product ranges change frequently, and availability depends on your circumstances.
Because offset ranges are smaller, the right offset deal for you may not be with your own bank. Comparing offset products against standard mortgages, with or without planned overpayments, is part of what a mortgage broker at Quanstrom Financial does when you remortgage or buy a home.
See how an offset could change your payments
If you choose lower monthly payments, your interest is worked out on your mortgage balance minus your linked savings. For a rough idea of the effect, enter your balance after deducting your savings in the calculator below, then compare it with your full balance.
[[calc:repayment]]
The calculator gives an illustration only and does not reflect any specific lender's offset product or rate.
How a mortgage broker at Quanstrom Financial can help
Quanstrom Financial is a whole-of-market mortgage broker based in Eastbourne, East Sussex, advising clients across the UK. We can compare offset mortgages with standard deals for your situation, show you roughly where the break-even point sits for your savings and tax band, and help you weigh flexibility against the lowest rate. We do not give tax advice, so for questions about your own tax position we would recommend speaking to an accountant or tax adviser alongside us.
Book a free consultation to talk through your options.
Frequently asked questions
Is an offset mortgage worth it for a higher-rate taxpayer?
It can be, particularly if you have substantial savings compared with your mortgage. Higher-rate taxpayers pay 40% tax on savings interest above £500 a year, rising to 42% from April 2027, so the tax-free benefit of offsetting is worth more to them, but it still needs to outweigh any higher rate charged on the rest of your mortgage.
How does an offset mortgage work?
Your savings are held in an account linked to your mortgage with the same lender, and the balance is deducted from your mortgage before interest is calculated. Your savings usually earn no interest, but you pay less mortgage interest, which can lower your monthly payments or shorten your term.
Are offset mortgage rates higher than standard mortgages?
Often, yes. Accord Mortgages says offset rates are likely to be higher than non-offset rates, and Coventry Building Society says they can be slightly higher. The size of the gap varies by lender and over time, which is why it needs to be part of any comparison.
Do offset mortgages still exist?
Yes, but fewer lenders offer them than in the past. Barclays, Coventry Building Society and Accord Mortgages all show offset products on their websites, while lenders such as First Direct and Hinckley & Rugby Building Society no longer offer them to new customers.
Is it better to offset or overpay my mortgage?
It depends on whether you might need the money back. Overpaying permanently reduces your mortgage and usually means a standard rate, while offsetting keeps your savings accessible at the cost of a rate that is often slightly higher. Neither is better in every situation.
Can I still access my savings with an offset mortgage?
Usually, yes. MoneyHelper notes that you can still withdraw your savings if you need to, although taking money out increases the balance you pay interest on. Some specialist family offset accounts restrict withdrawals, so check the terms of any account you link.
Is the interest saved with an offset mortgage taxed?
No. Because your linked savings do not earn interest, there is no savings income to tax. Lenders including Coventry Building Society point out that this is why offset mortgages can appeal to higher and additional-rate taxpayers, although tax rules can change in future.
Can family members link their savings to my offset mortgage?
With a small number of lenders. Some let relatives link their own savings to your mortgage, but rules on whose savings can be linked vary between lenders, so it is worth checking before you apply.
Can I get an offset mortgage on a buy-to-let?
It is much harder. Coventry Building Society and Accord Mortgages only offer offset on residential mortgages, so buy-to-let offset options are limited and depend heavily on your circumstances.
Written by Toby Quanstrom CeMAP, Director at Quanstrom Financial, a whole-of-market mortgage broker based in Eastbourne, East Sussex.
Tax figures are for the 2026/27 tax year and include changes announced in Budget 2025, correct as at 13 October 2026. Income tax bands differ for Scottish taxpayers. Quanstrom Financial does not provide tax advice. This article is general information only and does not constitute personal advice or a recommendation of any lender.
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