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Mortgage Calculator
Calculate your monthly mortgage payments and see the full amortisation schedule.
Repayment & Interest-Only
Both mortgage types with full cost comparison
Amortisation Schedule
Year-by-year breakdown of principal and interest
Total Cost Analysis
Monthly payment, total interest, and LTV ratio
Calculate Your Mortgage
Enter your property details to see monthly payments and total costs.
How Mortgage Repayments Are Calculated
The Mortgage Formula
Where M is the monthly payment, P is the loan amount, r is the monthly interest rate (annual rate / 12), and n is the total number of payments. Early payments are mostly interest; over time, the principal portion increases.
Repayment vs Interest-Only
With a repayment mortgage, each payment covers interest plus a portion of the principal. With interest-only, you pay only the interest each month — the loan balance never reduces. A £240,000 repayment mortgage at 4.5% over 25 years costs £1,334/month. Interest-only on the same loan costs £900/month, but you still owe the full £240,000 at the end.
Understanding Your Mortgage Costs
Monthly Payments
Each payment is split between principal and interest. In year 1, most of the payment is interest. By the final years, most goes to principal. This is why overpaying early in the mortgage has the biggest impact on total interest saved.
Total Cost Over the Term
On a £240,000 mortgage at 4.5% over 25 years, you pay £160,200 in interest — two-thirds of the original loan amount. Reducing the term to 20 years saves £38,000 in interest but increases monthly payments by £200.
How to Use This Mortgage Calculator
Enter Property Details
Property price, deposit amount, and mortgage term.
Set Rate & Type
Interest rate and repayment or interest-only.
View Payment Schedule
Monthly payment, amortisation chart, and year-by-year table.
Tips for Reducing Your Mortgage Costs
- Make overpayments. Even £100/month extra can save thousands in interest and years off your mortgage. Most lenders allow 10% annual overpayment penalty-free.
- Choose a shorter term. A 20-year mortgage costs more monthly but saves significantly on total interest compared to 25 or 30 years.
- Remortgage before your deal ends. SVRs are typically 2-4% higher than fixed deals. Start shopping 3-6 months before your fixed rate expires.
- Consider offset mortgages. Your savings offset the mortgage balance, reducing interest without locking up your money. Useful if you have significant cash savings.
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