Mortgage monthly repayment calculator

See what a mortgage payment would look like

The mortgage monthly repayment calculator turns an entered property price, deposit, interest rate and term into an illustrative payment. It is useful for comparing the effect of a larger deposit, a different term or a higher rate before building the rest of your household budget. It does not search mortgage products or decide what a lender will offer you.

Use figures from a mortgage illustration when you have one. Otherwise, label your chosen rate as an assumption and try more than one scenario. A rate used in a worked example is not a current market offer. A payment that fits a calculator budget is also separate from a lender’s assessment of income, commitments, credit and the property.

How the monthly payment is worked out

The opening loan is property price minus deposit plus any fees added to the loan. Fees paid upfront are shown separately and do not increase that balance. The loan-to-value result uses the price and deposit before financed fees, so it describes that specific ratio rather than a lender’s complete product assessment.

For a repayment mortgage, the calculator spreads repayment of capital and interest over the term. It uses a monthly rate equal to the annual percentage divided by 1,200. The payment formula is P × r ÷ [1 − (1 + r) raised to −n], where P is the opening loan, r the monthly rate and n the number of monthly payments. At zero interest, the loan is simply divided by the number of months.

For interest-only, the monthly figure is opening loan multiplied by the monthly rate. The capital remains due at the end. Neither calculation automatically provides a repayment plan for that final capital amount. Years and additional months combine into the term, so 25 years and six months means 306 payments in this model.

Worked example: repayment and interest-only

Take a hypothetical £250,000 property with a £50,000 deposit, no financed fee, a 5% assumed annual rate and a 25-year term. The loan is £200,000 and the repayment result is approximately £1,169.18 a month. The loan-to-value before fees is 80%. With the rate unchanged for the entire modelled term, total interest is approximately £150,754.02.

Switching those same inputs to interest-only produces approximately £833.33 a month, but leaves £200,000 principal due at the end. It is not an equivalent long-term outcome merely because the monthly figure is lower. If you also enter £500 in upfront fees, that money appears separately and does not alter either loan payment.

Make the result useful in a moving budget

The constant-rate assumption is central. A two-year fixed rate on a 25-year mortgage is not a promise of the same payment for 25 years. Actual lenders may calculate interest daily, round differently and set a first payment that reflects its particular timing. Read the lender’s illustration for the contractual details.

GOV.UK’s preparing-to-buy guidance explains that lenders consider income and outgoings when assessing borrowing. Use the borrowing scenario planner to explore a chosen payment ceiling, then the running-cost budget to add local charges, utilities, insurance and other commitments.

There is no single typical mortgage payment for UK movers: price, deposit, term, rate and repayment method all change it. Record separately any quoted product, legal or valuation fees. If comparing offers, the mortgage deal comparison considers fees and remaining balances over a common period instead of treating the lowest monthly payment as the whole answer.

How to use this tool

Enter the borrowing inputs. Supply the property price and deposit, then distinguish fees added to the loan from those paid upfront. The deposit cannot exceed the property price.

Choose a clear scenario. Enter the annual rate, years, additional months and repayment method. Keep a note of whether the rate is an actual illustration or a hypothetical assumption.

Budget beyond the payment. Review interest and any capital due at term end, then put the monthly figure alongside your other household costs and test a changed-rate scenario.

Frequently asked questions

Is the displayed rate a mortgage offer?

You enter the rate yourself. The tool does not provide live rates, an agreement in principle or lending approval, and it cannot confirm that a product is available to you.

Why are financed fees different from upfront fees?

A financed fee increases the opening loan and therefore affects interest and payments. An upfront fee needs separate cash but does not increase the principal used in this calculation.

Why might my lender quote a different payment?

The model assumes equal monthly periods and a constant nominal rate. Lender payment dates, daily interest, rounding and rate changes can differ; use the contractual illustration for the actual arrangement.