Overpayment calculator
Mortgage overpayment calculator
What a regular overpayment, a lump sum, or both together would do to your mortgage: how much sooner it clears and how much interest never gets charged.
- Bank of England base rate
- 3.75%
- 2-year fix, 75% LTV
- 4.92%
- 5-year fix, 75% LTV
- 4.77%
UK average quoted rates · Source: Bank of England, September 2026 · updated monthly. Reference data only — not a product offer and not advice.
Paid off sooner by
5y 4m
Interest saved
£103,033
New monthly payment
£3,928
Based on the current UK average of 4.77% for a 5-year fix at 75% LTV — Bank of England, September 2026. Updated monthly. Reference data only, not a product offer.
- Interest without overpaying
- £428,283
- Interest with overpayments
- £325,250
- Term after overpayments
- 19y 8m
Your figures, considered
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What you're looking for
Step 1 of 2Indicative only. This is not financial advice, a mortgage offer or a tax computation. Confirm the figures with a qualified broker, solicitor or tax adviser before you commit.
Questions we get asked
- How much can I overpay without a penalty?
- Most fixed-rate products allow ten per cent of the outstanding balance each year without an early repayment charge. Check your offer document before setting up a standing order, because the allowance is usually measured on a calendar or anniversary basis.
- Is it better to overpay monthly or in a lump sum?
- Interest is charged on the balance, so the sooner money comes off, the more it saves. A lump sum early beats the same amount spread across the year, but a regular overpayment is easier to sustain and compounds well over a long term.
- Should the overpayment reduce the term or the payment?
- Reducing the term saves far more interest, which is what this calculator assumes. Reducing the monthly payment gives you breathing room instead. Tell your lender which one you want, otherwise they will often choose for you.
- Does overpaying help when I come to sell?
- It lifts your equity, which widens the range of what you can buy next and improves the loan-to-value on your next deal. If you are weighing a move, start with a realistic view of what your home is worth today.