First-time buyer mortgage calculator
Work out your monthly payment on your first mortgage, see exactly how much of it is interest, and model what overpaying each month would save you over the full term.
With £0/month overpayment
Interest saved
£0
Time saved
0 months
Mortgage-free
—
Balance owed at end of term: £0. This is not included in the totals above. You will need a separate repayment strategy to clear it.
Outstanding balance over time
Year-by-year breakdown
| Year | Balance | Interest | Capital |
|---|
This is an illustration, not financial advice. Actual repayments vary due to lender fees, rate changes, and payment rounding. Get a personalised quote from a mortgage broker or lender before applying.
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OpenHow this is calculated
- We subtract your deposit from the property price to get the loan amount (also called the mortgage advance).
- We calculate the monthly repayment using the standard mortgage formula: payment = loan × (r × (1 + r)^n) ÷ ((1 + r)^n − 1), where r is the monthly interest rate (annual rate ÷ 12) and n is the number of months.
- During the fixed-rate period, every payment uses your initial rate. At the end of that period, we take the remaining balance and the remaining term, then recalculate the monthly payment at the follow-on rate.
- Each month we split the payment into interest (balance × monthly rate) and capital (the rest). The capital portion reduces your outstanding balance. Early payments are mostly interest; later payments are mostly capital.
- If you enter a monthly overpayment, we apply it on top of the required capital each month. This reduces the balance faster, cuts the interest charged in later months, and can shorten the term significantly.
- For interest-only mortgages, the monthly payment covers only the interest on the full balance. The balance stays the same throughout the term unless you make overpayments.
- The chart shows your outstanding balance at the end of each year. A second line appears when you enter an overpayment, showing how quickly the balance falls and when the mortgage would be cleared.
Frequently asked questions
How much deposit do I need as a first-time buyer?
The minimum is 5% for most lenders. A 10% deposit (90% LTV) opens a wider range of deals and typically lower rates. The step from 95% to 90% LTV is where you see the most meaningful rate improvement. A Lifetime ISA (LISA) lets you save up to £4,000 a year towards a first home and the government adds a 25% bonus — up to £1,000 per tax year.
Will I pay Stamp Duty as a first-time buyer?
In England and Northern Ireland, first-time buyers pay no Stamp Duty Land Tax (SDLT) on the first £300,000 of a property worth up to £500,000. In Scotland, Land and Buildings Transaction Tax (LBTT) applies from £145,000, with first-time buyer relief raising the nil-rate threshold to £175,000. Our <a href="/calculators/property/stamp-duty" class="underline">Stamp Duty & LBTT calculator</a> gives a full breakdown for your property price.
What is a fixed-rate mortgage?
Your interest rate is fixed for an initial period — typically 2, 3 or 5 years — regardless of what happens to the Bank of England base rate. After that period you move to your lender's standard variable rate (SVR), which is usually higher. Most first-time buyers remortgage to a new fixed deal at the end of their initial period rather than sitting on the SVR.
What is an interest-only mortgage?
Your monthly payment covers only the interest on the loan. The capital — the amount you borrowed — does not reduce. At the end of the term you owe the full original amount and need a separate repayment plan: savings, investments, or the sale of the property. Interest-only is rarely available to first-time buyers and typically requires a credible repayment strategy.
How much can I borrow as a first-time buyer?
Most UK lenders offer between 4 and 4.5 times your gross annual income. Some specialist lenders go up to 5.5 times for strong applicants, and certain government-backed schemes have their own criteria. Lenders also stress-test affordability at a higher notional rate to confirm you could still repay if rates rose. The affordability check on this page gives an indicative range.
How do overpayments work, and are there penalties?
Overpayments reduce your outstanding balance faster, which cuts total interest and can shorten your term significantly. Most fixed-rate mortgages allow overpayments of up to 10% of the outstanding balance per year without an early repayment charge (ERC). Exceeding that limit may trigger a penalty. On the SVR there are no ERC restrictions.
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This calculator is for general guidance only. It does not replace advice from a mortgage adviser or broker on your personal circumstances.
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