Mortgage Repayment Calculator
Calculate monthly mortgage repayments for repayment and interest-only mortgages. See total interest paid over the term.
Source: Bank of England — Base rate
By Konstantin Iakovlev · Founder, Calks.uk
Last updated: · Verified against HMRC and GOV.UK 2026/27 rates
Quick Answer
UK mortgage monthly payment uses the standard formula: M = P × r(1+r)^n / ((1+r)^n − 1) where P is loan, r is monthly rate, n is number of months. A £200,000 mortgage at 5% over 25 years costs about £1,169/month.
Monthly Payment
£1,389.58
Total Repaid
£416,874.36
Total Interest
£166,874.36
Borrowed
£250,000.00
Disclaimer
This calculator is provided for informational purposes only and should not be considered as financial or tax advice. All calculations are performed locally in your browser — no personal data is collected or sent to our servers. Rates and thresholds are sourced from HMRC and GOV.UK and are updated for the current tax year. Always verify results with HMRC or consult a qualified professional before making financial decisions.
How It Works
A repayment mortgage calculator uses the standard amortisation formula to calculate your fixed monthly payment. The formula accounts for the loan amount, annual interest rate and loan term to produce a payment that covers both interest and capital repayment, so the loan is fully repaid by the end of the term.
With a repayment mortgage, early payments are mostly interest, but over time the capital portion grows. An interest-only mortgage charges only the interest each month, leaving the full capital balance due at the end. This calculator supports both types and shows the total amount repaid over the life of the loan.
The calculation assumes a fixed interest rate throughout the term. In practice, most UK mortgages are fixed for 2-5 years before reverting to the lender's standard variable rate (SVR). Use the mortgage comparison features to compare different rates and terms side by side.
Repayment vs Interest-Only — the £200,000 example. On a £200,000 mortgage at 5% over 25 years: repayment costs £1,169/month (total cost £350,800; principal £200,000 + interest £150,800). Interest-only costs just £833/month but the full £200,000 must be repaid at the end. Most lenders require a credible repayment plan (investment ISA, pension lump sum) for residential interest-only. BTL mortgages are typically interest-only because rental income covers interest and capital growth covers the eventual balance.
How interest rate moves change your payment. A 1% rate rise on £200,000 over 25 years adds ~£110/month (£1,169 → £1,283). A 2% rise adds £230/month. For variable/tracker mortgages this hits immediately; for fixed-rate borrowers it hits at the end of the fix period. The Bank of England's 14 base rate hikes (2021-2023) plus 5 cuts (2024-2025) mean today's typical 5-year fix is 4.3-5.0%. Use the calculator's 'what if rates go up' to test affordability at +2% as the Mortgage Charter recommends.
Overpayments — the most powerful wealth lever. £100/month overpayment on a £200,000/5%/25-year mortgage cuts the term by 4 years 7 months and saves £35,000+ in interest. £200/month overpayment cuts ~7 years and £58,000. Most UK fixed-rate mortgages allow 10% annual overpayment penalty-free. After the fix ends, you can overpay without limit (subject to your lender). Overpaying early in the term has 2-3× the impact of overpaying late.
When to fix, when to track, when to remortgage. Fix when rates are stable/falling and you value certainty — 2-year fixes for short-term, 5-year for stability, 10-year for ultra-long-term. Track when you expect rates to fall — but check the 'collar' (some trackers have minimum rates). Discount mortgages (% below SVR) suit short-term borrowers. Remortgage 3-6 months before your current deal ends; use the 'product transfer' option with your current lender for speed, or shop the market for the best rate (usually saves 0.1-0.5%).
Repayment vs Interest-Only. £200k mortgage at 5% over 25 years. Repayment: £1,169/month (total cost £350,800; £200k principal + £150,800 interest). Interest-only: £833/month but full £200k must be repaid at end via separate plan. Most residential lenders require credible repayment plan (investment ISA, pension lump sum). BTL mortgages typically interest-only — rental income covers interest, capital growth covers eventual balance.
Interest rate movement impact. 1% rate rise on £200k/25 years adds £110/month (£1,169 → £1,283). 2% rise: £230/month. Variable/tracker mortgages: hits immediately. Fixed-rate: hits at end of fix period. BoE made 14 base rate hikes 2021-2023 + 5 cuts 2024-2025. Typical 5-year fix 2026: 4.3-5.0%. Use 'what if rates go up' to test affordability at +2% per Mortgage Charter recommendation.
Overpayments — most powerful wealth lever. £100/month overpayment on £200k/5%/25-year mortgage cuts term 4 years 7 months, saves £35k+ interest. £200/month overpayment cuts ~7 years and £58k. Most UK fixed mortgages allow 10% annual overpayment penalty-free. After fix ends, you can overpay unlimited. Overpaying early has 2-3× impact of late overpayments due to compound interest.
Fixed vs tracker — strategic decision. Fixed when rates stable/falling and value certainty: 2-year for short-term flexibility, 5-year for stability, 10-year for ultra-long-term. Tracker when expecting rates to fall — check 'collar' (minimum rates). Discount mortgages (% below SVR) suit short-term borrowers. Remortgage 3-6 months before deal ends; product transfer with existing lender for speed, shop market for best rate (typically saves 0.1-0.5%).
Example: £250,000 mortgage at 4.5% over 25 years
- Monthly repayment: £1,389.58
- Total repaid over 25 years: £416,874
- Total interest paid: £166,874
- Interest-only alternative: £937.50/month (capital still owed at end)
Source: Bank of England — Base rate
Frequently Asked Questions
- What is the difference between repayment and interest-only mortgages?
- A repayment mortgage requires monthly payments that cover both the interest charge and a portion of the outstanding capital, so the debt reduces each month and reaches zero at the end of the term. In the early years, most of the payment is interest; towards the end, most goes to capital. A £200,000 repayment mortgage at 4.5% over 25 years costs approximately £1,112 per month. An interest-only mortgage charges only the monthly interest — £750/month on the same loan — but the £200,000 capital remains outstanding and must be repaid in full at the end of the term. Most residential lenders require a credible repayment plan (such as an investment ISA or pension) before granting interest-only mortgages. Interest-only is more common for buy-to-let purchases. Source: FCA Mortgage Conduct of Business rules.
- How much deposit do I need for a UK mortgage?
- Most UK residential mortgage lenders require a minimum deposit of 5% of the property value, making the maximum loan-to-value (LTV) 95%. However, interest rates are significantly better at higher deposit levels. A 5% deposit (95% LTV) might attract a rate of 5.5–6%, while a 25% deposit (75% LTV) could secure 4–4.5%. For a £300,000 property, a 5% deposit is £15,000 with monthly repayments around £1,900 (at 5.5% over 25 years), versus a 25% deposit of £75,000 with repayments around £1,530 (at 4.25%). First-time buyers can access 5% deposit mortgages through the Mortgage Guarantee Scheme. Buy-to-let mortgages typically require 20–25% minimum. New-build properties may also have 5% options through developers. Source: FCA, major UK lenders.
- What happens if interest rates rise?
- The impact of interest rate rises depends entirely on your mortgage type. If you have a standard variable rate (SVR) or tracker mortgage, your monthly payments rise automatically when the Bank of England base rate increases — a 1% rate rise on a £200,000 outstanding balance adds approximately £167/month. Fixed-rate mortgages provide certainty for the fixed period: your payments do not change regardless of base rate movements. When a fixed period ends, you are moved to the SVR (usually 2–3% above base rate) unless you remortgage. A 2-year fixed deal taken in 2022 at 2% that expires in 2024 would face renewal at 4.5–5.5% — for many borrowers, an increase of £300–£500/month on the same balance. Using this calculator's overpayment feature during a low-rate period reduces the balance and therefore the impact of any future rate rise. Source: Bank of England, FCA.