Mortgage Overpayment Calculator UK — See How Extra Payments Save You Thousands
Calculate how much you can save by making regular or lump-sum overpayments on your UK mortgage. See how many years you can cut from your mortgage term.
Making even small overpayments on your UK mortgage can save thousands in interest and cut years off your mortgage term. Most UK mortgage lenders allow overpayments of up to 10% of the outstanding balance per year without early repayment charges. A monthly overpayment of just £200 on a £250000 mortgage at 4.5% saves approximately £35000 in interest and clears the mortgage 6 years early.
How much should I overpay on my mortgage?
Start with whatever you can comfortably afford even £50/month makes a difference. On a £200000 mortgage at 4.5%: £50/month overpayment saves £12000 and 2 years. £100/month saves £22000 and 4 years. £200/month saves £35000 and 6 years. Always ensure you have a 3-6 month emergency fund before committing to regular overpayments as you may not be able to get the money back.
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Loan Prepayment Calculator
How This Calculator Works
This calculator uses the standard reducing balance method to compute your monthly payments. The formula takes your loan principal, annual interest rate, and tenure to calculate the exact Equated Monthly Installment (EMI) or payment amount. Each monthly payment consists of two components — principal repayment and interest charges. In the early months, a larger portion goes toward interest, but as your outstanding balance decreases, more of each payment reduces the principal. This is why making extra prepayments in the early years of your loan saves significantly more interest than prepaying later.
Tips to Get the Best Loan Deal
Always compare the Annual Percentage Rate (APR) rather than just the advertised interest rate, as APR includes processing fees, insurance charges, and other costs. Negotiate your processing fee — most banks will reduce or waive it if you ask. Choose the shortest tenure your budget allows since longer tenures dramatically increase total interest paid. Check prepayment terms before signing — RBI mandates zero prepayment penalty on floating rate home loans in India. Finally, maintain a credit score above 750 to qualify for the best rates from any lender.
Key Information
| Parameter | Details |
|---|---|
| Typical Overpayment Allowance | 10% of balance per year (no penalty) |
| £200/month Overpayment Savings | ~£35000 interest saved on £250K |
| Years Saved with £200/month | Approximately 6 years on 25-year term |
| Annual Lump Sum Impact | £5000/year saves ~£40000 total |
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Use Calculator NowFrequently Asked Questions
How much should I overpay on my mortgage?
Start with whatever you can comfortably afford even £50/month makes a difference. On a £200000 mortgage at 4.5%: £50/month overpayment saves £12000 and 2 years. £100/month saves £22000 and 4 years. £200/month saves £35000 and 6 years. Always ensure you have a 3-6 month emergency fund before committing to regular overpayments as you may not be able to get the money back.
Should I overpay mortgage or invest in ISA?
With mortgage rates at 4-5% and stock market historical returns of 7-10% investing in a Stocks and Shares ISA mathematically beats overpaying on average. However mortgage overpayment is a guaranteed return at your interest rate with zero risk. Many financial advisors recommend doing both: overpay mortgage by a comfortable amount and invest the rest in ISA for long-term growth and tax-free returns.
Can I get mortgage overpayments back?
It depends on your lender. Some offer an overpayment reserve or borrow-back facility allowing you to reclaim overpayments. Most do not meaning once overpaid the money is locked in your property equity. Offset mortgages link your savings to your mortgage reducing interest while keeping savings accessible. Consider an offset mortgage if you want the benefits of overpaying with the flexibility of access.
What is a fixed vs variable rate mortgage?
A fixed rate locks your interest rate for 2-5 years, giving payment certainty. A variable (tracker) rate moves with the Bank of England base rate and can be lower initially but carries risk of increases. Most UK buyers choose a 2 or 5 year fix then remortgage when the fixed period ends.
How much deposit do I need for a UK mortgage?
The minimum deposit is typically 5-10% of the property value. A 10% deposit opens more competitive rates, and 25% or more gets the best deals. First-time buyers may access government schemes like Shared Ownership with smaller deposits. The bigger your deposit, the lower your LTV ratio and monthly payments.
What are the stamp duty rates for 2025-26?
Post-April 2025 SDLT rates: 0% on first £125,000, 2% on £125,001-£250,000, 5% on £250,001-£925,000, 10% on £925,001-£1,500,000, and 12% above £1.5 million. First-time buyers pay 0% up to £300,000 and 5% on the portion between £300,001-£500,000 (relief lost above £500,000).
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Last updated: March 2026