Mortgage Repayment Calculator
Monthly repayments, total interest and loan-to-value for a repayment mortgage, charted across the full term.
About your mortgage
What you'll repay
- Loan amount
- £272,000
- Loan to value
- 85.0%
- Total repaid
- £453,559
- Total interest
- £181,559
- Payments
- 300
- Amount borrowed60%
- Interest40%
- Remaining balance
Estimates only, based on published HMRC rates. Not financial advice.
A repayment mortgage is an amortising loan: every payment covers interest first, and whatever's left reduces the balance. That ordering explains almost everything about how mortgages behave.
How to use it
- 1Enter the property price and your deposit.
- 2Set the interest rate and term.
- 3Read the monthly repayment, total interest, LTV and balance chart.
How the monthly payment is calculated
The payment is fixed so that the balance reaches exactly zero at the end of the term. It's derived from the amount borrowed, the monthly interest rate and the number of payments, using the standard annuity formula.
Because interest is charged on the outstanding balance, early payments are mostly interest and late payments are mostly capital. On a typical 25-year mortgage, you'll be several years in before the split gets close to even, which is why the balance chart looks like a shallow curve rather than a straight line.
Loan to value, and why it dominates your rate
Loan to value is the mortgage as a percentage of the property's value. Lenders price in bands, typically at 60%, 75%, 80%, 85%, 90% and 95%, and the difference between adjacent bands can be substantial across a whole term.
This makes small deposit increases disproportionately valuable near a threshold. Adding a few thousand pounds to move from 81% to 79% LTV can save more over the term than the deposit itself, and it's worth checking where you sit before fixing the numbers.
Term length and overpayments
A longer term lowers the monthly payment and raises the total interest, sometimes dramatically. Stretching 25 years to 35 makes the monthly figure comfortable and can add well over a hundred thousand pounds of interest on a large loan.
Overpayments work in the opposite direction and are unusually effective early on, because every pound overpaid removes all the future interest that pound would have accrued. Most lenders allow overpayments of up to 10% of the balance each year without penalty; beyond that, early repayment charges usually apply during a fixed period.
What this calculator doesn't include
It models the mortgage itself. Buying a home also involves stamp duty, valuation and legal fees, surveys, buildings insurance, ground rent and service charges on leasehold property, and moving costs. Budget for those separately, they typically add several thousand pounds on top of the deposit.
Common questions
- How much can I borrow for a mortgage?
- Lenders commonly cap borrowing at four to four and a half times income, subject to an affordability assessment covering your outgoings and a stress test at a higher rate. Your deposit and credit history then shape the rate offered.
- Is it better to overpay or shorten the term?
- Financially they're similar, but overpaying keeps flexibility, you can stop any month. Shortening the term locks in a higher required payment. Overpaying early saves the most interest either way.
- What is loan to value?
- The mortgage as a percentage of the property value. A £240,000 mortgage on a £300,000 home is 80% LTV. Lower LTV generally means access to better rates.
- Why is so little of my early payment reducing the balance?
- Interest is charged on the outstanding balance, which is at its largest at the start. As the balance falls, the interest portion shrinks and the capital portion grows.
- Does this include fees and stamp duty?
- No. It calculates the mortgage repayment only. Arrangement fees, stamp duty, legal costs and surveys need budgeting separately.