A mortgage overpayment calculator helps you determine how much interest you can save and how much sooner you can pay off your mortgage by making extra payments. It supports both lump sum payments and regular monthly overpayments.
Yes, especially early in the loan term. Mortgage interest is calculated on the remaining principal, so extra payments directly reduce the principal and significantly lower future interest. For a $300,000 30-year mortgage, paying an extra $30,000 could save over $60,000 in interest.
It depends on your financial situation. A lump sum payment saves interest immediately; monthly overpayments are more manageable for those with steady income. You can combine both approaches.
Completely safe. All calculations are performed locally in your browser. Your loan amount, interest rate, and other sensitive data are never uploaded to any server. The tool works offline too.