TL;DR: An offset mortgage is a home loan linked to a savings account, where your savings reduce the mortgage balance you’re charged interest on. It works well for self-employed borrowers, higher-rate taxpayers and anyone with decent savings. Your savings stay accessible, but they won’t earn interest. A mortgage broker can help you compare offset deals against standard mortgages.
An offset mortgage uses your savings to reduce the amount of interest you pay on your home loan, without locking your money away. On a £500,000 mortgage over 25 years, the total interest bill can easily exceed £330,000.
By offsetting savings against that balance, you could cut that figure by tens of thousands of pounds.
Most people focus on finding the lowest interest rate, and rightly so. But there’s another way to reduce what you pay in interest, and it involves putting your savings to work. If you have cash sitting in a savings account earning a poor return, an offset mortgage could help that money do something far more useful.
In this guide, we’ll explain how offset mortgages work, who they suit best, and how to work out whether one could save you money. We’ve also included a table of figures so you can see the potential savings at a glance.
What Is an Offset Mortgage?
An offset mortgage is linked to a savings account held with the same lender.
Rather than earning interest on these savings, that money is used to reduce the mortgage balance on which you’re charged interest. Your savings aren’t used to pay off the mortgage itself. They simply sit alongside it, reducing the amount the lender calculates interest on.
How the numbers work
Say you have a £500,000 mortgage and £75,000 in savings. With an offset mortgage, you’d only pay interest on £425,000. (500k – 75k = 425k)
The lender recalculates this daily, so even short-term deposits in the savings account will have some effect.
Your savings stay in the account and remain yours. You can withdraw them whenever you need to, though the more you keep in there, the less interest you’ll pay on your mortgage each month.
Offset mortgages have been around for quite some time but are still relatively uncommon.
According to FCA data published in July 2025, only around 155,500 UK mortgages had an offset facility at the end of 2024, representing just 1.7% of all outstanding mortgages. That figure has fallen from 2.9% in 2020, partly because fewer lenders now offer these products.
How Much Can You Save with an Offset Mortgage?
The amount you save depends on the size of your mortgage, the amount in your linked savings account and the interest rate.
To give you a clearer picture, here are some worked examples.
Offset mortgage savings table
The table below is based on a £500,000 repayment mortgage over 25 years at an assumed rate of 4.5%. It shows what happens when different amounts are held in the offset savings account.
| Savings offset | Interest charged on | Monthly payment | Monthly saving | Total interest saved over 25 years |
|---|---|---|---|---|
| £0 (no offset) | £500,000 | £2,779 | – | – |
| £25,000 | £475,000 | £2,640 | £139 | £16,690 |
| £50,000 | £450,000 | £2,501 | £278 | £33,370 |
| £75,000 | £425,000 | £2,362 | £417 | £50,060 |
| £100,000 | £400,000 | £2,223 | £556 | £66,750 |
These figures are calculated using standard UK mortgage amortisation formulas for a repayment mortgage. They assume the savings balance and interest rate remain constant throughout the full 25-year term. They are for illustration only and do not represent a specific lender’s product.
Even £25,000 in savings could reduce your interest bill by close to £17,000 across the mortgage term. With £100,000 in savings, the interest saving rises to nearly £67,000. Those are figures worth paying attention to.
Reducing your mortgage term
There’s another way to use the offset benefit.
Instead of lowering your monthly payments, you can keep paying the original amount each month. Because less of each payment goes towards interest, more goes towards paying off the capital, and this shortens your mortgage term.
It’s an alternative way of overpaying your mortgage.
Using the same example above with £75,000 in savings, keeping the original payment of £2,779 could reduce your mortgage term by around six years. That’s six fewer years of payments, and the total interest saving would be even greater than the figures shown in the table because you’re clearing the debt sooner.
Who Benefits Most from an Offset Mortgage?
Offset mortgages aren’t for everyone, but they work well for certain groups of borrowers. If you fall into one of these categories, it’s worth looking into.
Self-employed borrowers
If you’re self-employed, you probably set aside money throughout the year to cover your tax bill. With a standard savings account, that money earns a modest return while it waits to be paid to HMRC.
With an offset mortgage, those tax reserves reduce your mortgage interest every single day they’re in the account.
Once your tax bill is due, you withdraw the money and pay HMRC as normal. In the meantime, those funds have been working to cut your mortgage costs. For sole traders and company directors who keep meaningful cash balances, this can add up to real savings over the course of a year.
Higher-rate taxpayers
If you earn above the higher-rate threshold, any interest you earn on savings above your Personal Savings Allowance is taxed at 40%. For the 2025/26 tax year, the allowance is £1,000 for basic-rate taxpayers and £500 for higher-rate taxpayers.
With an offset mortgage, your savings don’t earn interest at all, so there’s nothing to declare and nothing to pay tax on. The benefit you receive comes through lower mortgage interest instead, and that benefit is completely tax-free.
For a higher-rate taxpayer, this can make offset mortgages more attractive than they first appear. A standard savings account would need to offer a rate well above the mortgage rate, after tax, to match the same benefit.
How Do Family Offset Mortgages Work?
A family offset mortgage allows parents or grandparents to link their own savings to a relative’s mortgage. A parent with, say, £60,000 in savings could use that money to reduce the interest on their child’s mortgage without actually giving the money away.
The savings remain in the parent’s name and they can withdraw them at any point. It’s a way of helping a son or daughter get on the property ladder, or reduce their housing costs, without the risk of gifting a large sum. For families where the older generation has savings but the younger generation is stretched by mortgage costs, this can be a very practical solution.
Not all lenders offer family offset products, so you’d need a broker to help you find the right deal.
Can You Still Access Your Savings?
Yes. One of the main benefits of an offset mortgage is that your savings remain accessible.
The money isn’t locked away and you’re not obliged to leave it there. You can add to your savings at any time, which increases the offset benefit, and you can withdraw money when you need it.
Keep in mind that withdrawals reduce your offset benefit. If you take out a large sum, the amount of mortgage interest you pay will rise until the balance is restored.
It’s a flexible arrangement, but it works best when you can keep a consistent balance in the account.
What is a family deposit mortgage?
Family members wanting to help you buy a home can transform your mortgage options – even if they can’t give you the money directly. Family deposit mortgages let your loved ones support your property purchase using their savings or property as security, without having to hand over a cash deposit.
Should You Choose an Offset Mortgage or a Bigger Deposit?
You might be wondering why you wouldn’t just use your savings as a bigger deposit. After all, both approaches reduce the amount you’re paying interest on.
The answer comes down to flexibility and access.
When a bigger deposit might work better
Putting your savings towards a larger deposit means you’ll borrow less and your loan-to-value ratio (LTV) will be lower. A lower LTV often means access to better interest rates and a wider choice of mortgage products.
Since offset mortgages are less common than standard deals, you may find that a standard mortgage with a lower rate and bigger deposit actually costs you less overall.
On the other hand, once you’ve used your savings as a deposit, that money is gone. You can’t get it back without selling or remortgaging the property. With an offset mortgage, you keep control of your cash. If something unexpected comes up, you can access your money without any penalties.
A whole of market mortgage broker can compare both options and show you which one saves you more in the long run.
What Are the Pros and Cons of an Offset Mortgage?
Like any mortgage product, offsets have their strengths and weaknesses. Here’s a balanced look at both sides.
The pros
The main advantages of an offset mortgage:
- You pay less mortgage interest while keeping full access to your savings
- Your savings effectively earn a return equal to your mortgage rate, which is often better than what savings accounts offer
- There are no tax implications because your savings don’t earn interest
- You can reduce your monthly payments, or keep them the same and shorten your mortgage term
- Family members can link their savings to help reduce your costs
The cons
The main disadvantages of an offset mortgage:
- Your savings won’t earn any interest, so inflation will erode their buying power over time
- Offset mortgage rates tend to be slightly higher than standard mortgage rates
- Fewer lenders offer offset products, so your choice is more limited
- If your savings are modest, the benefit may not outweigh the higher rate
- You may get a better overall deal by using your savings as a bigger deposit
Is an Offset Mortgage Right for You?
An offset mortgage works best when you have a meaningful amount of savings and you want to keep access to that cash.
It’s well suited to self-employed borrowers with tax reserves, higher-rate taxpayers looking for tax efficiency, or parents wanting to help their children with mortgage costs.
If your savings are modest, or you’re unlikely to keep a consistent balance in the account, a standard mortgage with a lower rate is probably the better option. The slightly higher interest rate on offset products means you need enough savings to make the offset benefit worthwhile.
The best way to find out is to speak with a whole of market mortgage broker.
They can compare offset deals against standard mortgages, run the numbers for your specific situation and help you choose the option that saves you the most money.
Frequently Asked Questions
There’s no fixed minimum, but most brokers suggest having at least 10-15% of your mortgage balance in savings before the offset makes a real difference. With a £500,000 mortgage, that means around £50,000 or more. Below that level, the slightly higher interest rate on offset products may cancel out the benefit you gain from offsetting.
Yes. Several UK lenders offer fixed-rate offset mortgages, usually over two or five-year terms. You get the certainty of fixed monthly payments combined with the flexibility of offsetting your savings. The range of fixed-rate offset products is smaller than standard fixed rates, so a broker can help you find what’s available.
Some lenders allow you to link both your current account and savings accounts to your offset mortgage. Your everyday cash balance would then also reduce the interest you pay. Not all lenders offer this feature, so ask your broker which products include current account offsetting.
Your mortgage continues as normal, but you lose the offset benefit entirely. You’d pay interest on the full mortgage balance until you build your savings back up. There are no penalties for withdrawing, and you can deposit money back into the account at any time to restart the offset.
They’re similar but not identical. A current account mortgage combines your mortgage, savings and current account into one single product. An offset mortgage keeps them separate but links them for the purpose of calculating interest. Offset mortgages are more widely available today, as most current account mortgage products have been withdrawn from the market.
Yes. Offset mortgages on residential properties are regulated by the Financial Conduct Authority (FCA), just like any other residential mortgage. Your lender and mortgage broker must both be FCA-authorised. This gives you access to the Financial Ombudsman Service and the Financial Services Compensation Scheme if something goes wrong.
