Skip to content
calculatorzone

Mortgage Calculator

Estimate UK mortgage repayments, total interest, and LTV. Compare loan amounts, rates, repayment types, and terms before requesting a quote.

Last reviewed: 3 August 2026Source: MoneyHelper — mortgage calculator guidance
Mortgage Calculator · UKFinance & Mortgages
Try:

Results update when you select Calculate.

Example result based on the prefilled values.

Monthly Payment

£1,228.17

Total Interest

£168,452.50

LTV

80.00%

Continue your plan

Useful next calculations

Related to this calculation

Compare a remortgage properly

Include fees, ERCs, cashback, remaining balance and the switching break-even month.

Plan the full cost of moving

Carry sale equity through selling, buying, tax, mortgage and removal costs.

Rates & sources

Illustrative monthly payment using the standard annuity formula. The rate is supplied by the user and must be checked against a lender’s personalised illustration.

FormulaP × r(1+r)ⁿ / ((1+r)ⁿ − 1)
Typical UK LTV bands60% / 75% / 85% / 95%
Rate assumptionentered by you
Binding comparisonlender ESIS / illustration

Source: MoneyHelper — mortgage calculator guidance — check the linked guidance and any live quote before acting.

When to use this calculator

  • Before comparing lenders, brokers, or repayment options.
  • When you want to test how a different deposit, rate, or term changes affordability.
  • When you need a quick estimate before using a formal quote or agreement in principle.
  • When you are stress-testing your budget against a potential rate rise to see the impact on monthly payments.
  • When you want to understand the full cost of borrowing — not just the monthly figure — before you commit.

Example: estimating repayments with a 20% deposit

Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.

Property value

£250,000

Deposit

£50,000

Mortgage required

£200,000

Rate and term

5.25% over 25 years

Review the monthly repayment and total interest together. Then increase the rate and shorten the term in separate runs to see whether the budget has enough headroom and whether a higher payment could materially reduce lifetime interest.

How to read your results

Monthly Payment

Use this to check whether the scenario fits comfortably within your regular budget. If it looks tight, rerun the tool with a longer term or larger deposit to find the boundary of affordability.

Total Interest

This shows the long-run cost of borrowing beyond the original principal, which is especially useful when comparing terms or weighing up overpayment options. A shorter term usually cuts this figure significantly even if the monthly payment rises.

LTV

Loan-to-value helps you compare product eligibility and understand how much lender risk you are carrying at this deposit level. Crossing key LTV thresholds — typically 90%, 85%, or 75% — can unlock materially better interest rates.

Method & assumptionsAuthoritative sources

This calculator works on a standard capital and interest repayment basis, spreading your loan across the chosen term so that each monthly payment reduces the outstanding balance while also covering interest. The calculation uses compound interest applied monthly, which is how virtually all UK residential mortgage lenders price their products. The result shows an illustrative monthly payment based on the rate and term you enter — it does not account for mortgage fees added to the loan, payment holidays, or rate changes at the end of a fixed period. Real-world repayments may differ slightly depending on how your lender calculates daily interest. Always request a full Key Facts Illustration (KFI) or European Standardised Information Sheet (ESIS) from any lender before committing.

Official references

Common mistakes

  • !Mixing up loan amount and property value, which can distort affordability and LTV.
  • !Using a headline rate but forgetting fees, insurance, taxes, or repayment type.
  • !Testing only one term length instead of comparing the payment and total cost together.
  • !Forgetting that a repayment mortgage and an interest-only mortgage produce very different monthly figures and total costs.
  • !Not accounting for the impact of a rate revert after an introductory fixed period ends, which can sharply increase payments.

What to do next

  • Stress-test the same balance at a higher rate so the payment does not only work under today’s assumption.
  • Check affordability against household income and committed outgoings, not just the lender’s headline loan size.
  • Add SDLT, legal fees, survey costs, and moving expenses to the cash needed before making an offer.

Go deeper — 4 guides reference this calculator

Frequently asked

This calculator uses the standard amortisation formula to compute monthly payments based on loan amount, interest rate, and term. The formula accounts for compound interest accrued monthly over the loan period.

Use arrow keys to navigate items, Enter or Space to expand/collapse.