Mortgage Overpayment Calculator (UK)

Making regular overpayments on your mortgage can save you thousands of pounds in interest and help you become mortgage-free years earlier. Use our free calculator to see exactly how much you could save based on your current mortgage position.

This calculator helps you understand the real impact of mortgage overpayments. Whatever value you're considering overpaying, you'll see a clear breakdown of:

  • How many years you'll save on your mortgage term
  • Total interest savings over the life of your mortgage
  • Year-by-year breakdown of your balance reduction
  • Visual comparison of your mortgage with and without overpayments

Our calculator supports two overpayment methods: fixed annual overpayments based on your original mortgage balance, or flexible overpayments that recalculate each year based on your remaining balance.

Calculate Your Savings

See how much you could save in seconds

Amount you currently owe

Years left on your mortgage

Your current annual rate

Your current monthly payment

Percentage to overpay each year (most lenders allow up to 10%)

Overpayment recalculated yearly based on remaining balance

Remortgage Points (Optional)

Add one or more remortgage events during your mortgage term

Frequently Asked Questions

How do mortgage overpayments work?

Mortgage overpayments are additional payments you make on top of your regular monthly mortgage payment. These extra payments go directly towards reducing your mortgage balance, which in turn reduces the amount of interest you pay over time. Learn more about how overpayments work.

Is it better to overpay my mortgage?

Overpaying your mortgage can be a smart financial decision as it reduces your debt and saves you money on interest. However, you should consider your personal circumstances, including whether you have high-interest debt elsewhere or if you could achieve better returns through investments. Read our guide on whether to overpay.

What is the 10% overpayment rule?

Many UK mortgage lenders allow you to overpay up to 10% of your outstanding balance each year without incurring early repayment charges (ERCs). Check your mortgage terms to understand your specific overpayment allowance. Learn about the 10% rule.

How accurate is this calculator?

This calculator uses standard mortgage mathematics to provide accurate estimates. However, actual results may vary depending on your lender's specific terms, how they apply overpayments, and when payments are made. Always verify with your mortgage lender before making overpayments.