Mortgage overpayment: should you overpay or save?

What is a mortgage overpayment?

A mortgage overpayment is any payment above the monthly amount your mortgage contract requires, made as a regular extra sum or as a one-off lump sum. It comes off what you owe, so less interest builds up and the loan can be cleared sooner. How overpaying compares with saving depends on your mortgage rate, the interest you keep on savings after tax, and whether you may need the money back.

This guide explains how a mortgage overpayment works, the limits and charges to check first, and the considerations on each side of the overpay or save question. It is information, not advice, and it reaches no verdict for you.

For the saving in pounds on your own loan, use the mortgage overpayment calculator.

How overpaying a mortgage works

On a repayment mortgage, each monthly payment covers that month's interest and repays a little of the loan. Interest is charged on what you still owe. An overpayment reduces what you owe ahead of schedule, so every later month's interest is worked out on a smaller balance.

Two details vary by lender: when an overpayment is credited to the balance, and what happens to your monthly payment afterwards.

Reduce the term or reduce the payment

After an overpayment, lenders commonly do one of two things.

Lenders differ in which they do by default, and some let you choose. If the aim is to finish early, the detail to check is whether your payment will be reduced automatically.

There is also a formal route: asking the lender to shorten the term, which raises the contractual payment. Since 22 July 2025 the Financial Conduct Authority (FCA) no longer requires a full affordability assessment for a term reduction, although lenders must still consider affordability and may choose how they apply the change. In making that change, the FCA said that for many customers, overpaying within the existing contract will be a more flexible way of repaying earlier. An overpayment is voluntary, while a shorter term raises the payment you are contractually bound to make.

The same idea applies to an interest only mortgage: an overpayment there reduces the loan itself, which the monthly payment never does.

Overpayment allowances and early repayment charges

The annual allowance

Mortgages on a fixed rate, and other deals that carry an early repayment charge, commonly limit how much you can overpay each year without a charge. MoneyHelper says many lenders let you overpay up to 10% a year without a charge. That figure is common, not a rule: no regulation sets it, and each lender sets its own terms for each deal. The terms can differ in ways that matter:

• The allowance may be a share of the original loan or of the balance at a set date.
• The year may be a calendar year or run from the anniversary of the mortgage.
• An unused allowance may or may not carry forward.
• Regular and lump sum overpayments may count towards the same limit.

Where a mortgage has no early repayment charge, which is often the case on a lender's standard variable rate, there is no such charge to pay on an overpayment, though the contract may set other conditions. The guide to the standard variable rate explains that rate.

Early repayment charges

If you overpay beyond the allowance, the lender can apply an early repayment charge where the contract provides for one. Under FCA rules the charge must be able to be expressed as a cash value and be a reasonable pre-estimate of the lender's costs from early repayment, and the maximum charge is set out in your mortgage illustration and offer. The FCA's 2025 rule changes did not alter when a charge applies under an existing contract.

The guide to mortgage fees covers early repayment charges and exit fees in more detail.

Should I overpay my mortgage or save?

There is no single answer to the overpay or save question, because it turns on your rates, your tax position and your need for access. This section sets out the considerations and leaves the weighing to you.

The mortgage rate against savings interest after tax

Every pound overpaid stops costing you interest at your mortgage rate, and that saving is not taxed. A pound saved earns the savings rate, less any tax on the interest. So the comparison is your mortgage rate against the savings rate you keep after tax. An offset mortgage is a third route: the savings stay yours and are set against the loan, so they cut the interest without being paid in.

On savings interest, GOV.UK sets out these allowances, which apply each tax year (6 April to 5 April):

• The Personal Savings Allowance lets basic rate taxpayers earn £1,000 of interest tax free and higher rate taxpayers £500. Additional rate taxpayers have no allowance.
• If your other taxable income is less than £17,570, the starting rate for savings can make up to £5,000 of interest tax free. Every £1 of other income above the Personal Allowance reduces it by £1.
• Interest earned in an Individual Savings Account (ISA) is tax free.

Interest above those allowances is taxed at your usual rate of Income Tax. With the higher rate of Income Tax at 40% and the basic rate at 20%, a higher rate taxpayer who has used the allowances keeps 60% of any further interest, and a basic rate taxpayer keeps 80%.

Rates on both sides move. The mortgage rates comparison shows what lenders publish today, and your own rate is on your latest statement.

An emergency fund

Money paid into a mortgage is hard to take back. Unless your mortgage has a feature that lets you draw overpayments down again, getting the money back means borrowing afresh, which the lender can refuse. MoneyHelper, the government-backed guidance service, gives as a rule of thumb three to six months of essential outgoings held in an instant access savings account for emergencies.

Dearer debts

Credit cards, overdrafts and personal loans often charge more than a mortgage. A pound that clears debt at a higher rate saves more interest than a pound that clears debt at a lower rate.

A pension

Pension contributions attract tax relief. GOV.UK explains that you can get relief on private pension contributions worth up to 100% of your annual earnings, and that under relief at source the pension provider claims relief at the basic 20% rate and adds it to your pot. An employer may also add contributions of its own. The trade-off is access: pension savings cannot normally be reached until later life.

Overpay or save, side by side

Overpaying a mortgage by small amounts

Small regular overpayments work in the same way as large ones. Each one reduces the balance for the rest of the term, so its effect builds over the years. An overpayment made early in a mortgage saves more interest than the same sum paid late, because it has longer to work.

How much a given amount saves depends on your balance, rate and remaining term. The mortgage overpayment calculator shows the interest saved and the time taken off for any monthly or one-off amount, and the mortgage calculator shows the payment itself.

Lump sum or monthly overpayments

Both count as overpaying a mortgage, and you can combine them.

• A lump sum cuts the balance at once, so the interest saving starts immediately. A large one can also exceed an allowance in a single payment.
• Monthly overpayments spread the cost and are simple to budget for. Lenders commonly let you set one up alongside your normal payment and stop it later.

With a lump sum on hand, the timing question is whether to pay it now, within this year's allowance, or to hold it until the early repayment charge period ends. Holding it in savings keeps it accessible in the meantime.

How overpaying affects loan to value at remortgage

Loan to value is the mortgage as a share of the home's value, and lenders price their deals in bands of it. Overpaying reduces the loan, so it lowers your loan to value even if the home's value does not move. Crossing into a lower band can open deals with different rates when your current deal ends.

The guide to loan to value explains the bands, and the guide to remortgaging explains the switch itself. The remortgage calculator compares the options with fees included.

Mortgage overpayment on a new build

Buyers of new homes often start with a small deposit and so a high loan to value. Two points follow for the first few years.

First, when you come to remortgage, the lender values the home as it stands in the market then, which may be above or below the price you paid the builder. A smaller balance gives you more room if the valuation is lower than you hoped. The guide to new build mortgages explains how lenders value new homes.

Second, the first year in a new home can bring its own costs, from furnishing to service charges, which is one more call on savings you can reach. If you bought with an equity loan, that is a separate debt with its own repayment rules, and overpaying the mortgage does not reduce it.

Paying off your mortgage early

Enough overpayments, or one final lump sum, clear the mortgage before the end of the term. Before paying off a mortgage early, check three things:

1. Whether an early repayment charge applies. Inside a fixed deal, repaying the whole loan normally triggers it.
2. Whether the lender charges an exit or closing fee.
3. The exact amount needed on the day, which the lender sets out in a redemption statement.

Once the loan is repaid, the lender releases its charge over the property. In England and Wales the lender tells HM Land Registry, either electronically or on a form called a DS1, so the charge can be removed from the register.

Being mortgage free ends the monthly payment, but not the other costs of owning a home, such as buildings insurance and maintenance.

Before you overpay: a checklist

1. Find your deal's overpayment allowance and the period it covers.
2. Check the early repayment charge for going over it.
3. Ask whether an overpayment shortens the term or lowers your payment.
4. Set your mortgage rate beside the savings rate you would keep after tax.
5. Note what you hold in savings you can reach, and any dearer debts.
6. Run your figures through the mortgage overpayment calculator.

The mortgage hub gathers the calculators, the lenders' published rates and the other mortgage guides.