Calculate your monthly repayment, total interest, and full amortisation schedule for any home loan.
A UK mortgage repayment is calculated using the standard amortisation formula M = P × [r(1+r)^n] ÷ [(1+r)^n − 1]. The Bank of England base rate drives variable products; fixed-rate deals price off SONIA swap rates. The FCA's Mortgage Conduct of Business handbook governs UK affordability rules.
UK mortgage maths in 2026 sits in a meaningfully different regime from the pre-2022 era of sub-2% rates. Borrowers refinancing from deals struck in 2018-2021 are landing in 4-5% products, and the affordability stress test embedded in lender models has materially compressed how much most households can borrow.
This calculator handles the four mortgage products UK borrowers actually use:
Beyond the headline rate, the calculator handles: - Capital repayment vs interest-only — capital repayment is the default for residential; interest-only is typically restricted to buy-to-let or high-net-worth lending - Term length — 25 years is standard, but 30-35 year terms are increasingly common to pass affordability. Extending term raises lifetime interest cost materially - Loan-to-value tiers — pricing steps at 60% / 75% / 85% / 90% / 95% LTV. Below 60% gets the best rates; 95% LTV (via the Mortgage Guarantee Scheme) carries the biggest premium - Affordability — lenders cap at 4-4.5x income, with FCA-mandated stress-testing against SVR+1% - Stamp Duty Land Tax — separate calculation; first-time buyers pay no SDLT up to £425,000 in England/NI
For underlying rules, the FCA's MCOB handbook governs UK mortgage advice and the Bank of England's monthly Money and Credit statistical release covers current SME and household lending rates. HMRC's Stamp Duty Land Tax calculator on gov.uk handles the SDLT calculation separately.
Calculate your monthly repayment, total interest, and full amortisation schedule for any home loan.
A standard fixed-rate mortgage uses the amortising annuity formula: M = P × r(1+r)n / ((1+r)n−1), where P is the loan amount, r is the monthly interest rate (annual ÷ 12), and n is the total number of monthly payments. Most of each early payment goes to interest; the principal share grows over time.
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This calculator implements the standard mortgage amortisation formula: M = P × [r(1+r)^n] / [(1+r)^n − 1]. Region-specific tax and rate defaults are sourced directly from each country's primary government source and reviewed against the publication date below.
Last verified: May 2026.