Mortgage Calculator UK
Enter your property price, deposit, interest rate and mortgage term to instantly calculate your monthly repayments, total interest and the full cost of your mortgage.
Monthly Repayment
Loan to Value
90.0%
Total Interest
£150,186.92
Total Repayment: £375,186.92
How Your Monthly Mortgage Repayment Is Calculated
Your monthly repayment depends on four things: how much you are borrowing, the interest rate, the mortgage term and whether you choose a repayment or interest-only mortgage.
For a repayment mortgage, lenders use a standard amortisation formula that ensures your balance reduces to zero by the end of the term:
Monthly Repayment = P × r × (1 + r)^n ÷ ((1 + r)^n − 1)
P = Loan amount (property price minus your deposit)
r = Monthly interest rate (annual rate ÷ 12)
n = Total number of monthly payments (years × 12)
Working example: You are borrowing £220,000 over 25 years at an interest rate of 4.5%. Your monthly repayment would be approximately £1,222. Over the full term you would repay around £366,600 in total, meaning roughly £146,600 of that is interest.
For an interest-only mortgage calculation is simpler: you pay only monthly interest (loan amount × annual rate ÷ 12) and original loan stays same throughout the term.
Repayment Mortgage vs Interest-Only
Example based on borrowing £220,000 over 25 years at 4.5% interest:
| Metric | Repayment Mortgage | Interest-Only |
|---|---|---|
| Monthly payment | ~£1,222 | ~£825 |
| Total paid over term | ~£366,600 | ~£247,500 + £220k capital |
| Capital repaid monthly | Yes, gradually | No, lump sum at end |
| Total interest paid | ~£146,600 | ~£247,500 |
Most residential buyers in the UK choose repayment mortgages. With a repayment mortgage you pay more each month but own the property outright at the end. With interest-only you pay less each month but must have a credible repayment strategy to clear the capital at the end of the term.
Types of UK Mortgages Explained
Fixed Rate Mortgage
Your interest rate is locked in for a set period, typically 2, 3 or 5 years. Your monthly repayment stays same for that period regardless of what happens to the Bank of England base rate.
Tracker Mortgage
Your rate follows the Bank of England base rate plus a set percentage. If base rate falls your repayments fall too. Sitting at base rate plus ~0.60% in April 2026.
Standard Variable Rate (SVR)
The rate your mortgage automatically reverts to when your deal expires. Averaging over 7% in 2026, significantly higher than available deal rates.
Discount Rate Mortgage
Your rate is set at a fixed percentage below the lender's SVR for an agreed period. Payments shift when the lender changes their SVR.
What Is Loan to Value (LTV) and Why Does It Matter?
Loan to Value is simply the size of your mortgage as a percentage of the property's value. The lower your LTV, the better the interest rates available to you.
The Formula:
LTV = (Loan Amount ÷ Property Value) × 100
Most lenders offer their most competitive rates at 60% LTV or below. Every 5% extra you can add to your deposit moves you into a better LTV band and typically unlocks a meaningfully lower rate.
The 2026 Rate Environment: What Borrowers Need to Know
The Bank of England base rate is currently 3.75%, held at its March 2026 meeting. Most analysts anticipate further rate cuts in 2026.
5-Year Fixed Rates
One of the lowest available deals in April 2026 is 4.25%.
Advice for Borrowers
Compare rates at least 3 to 6 months before your deal expires.
What the Lender Actually Checks
Lenders do not simply look at rate you are applying for. They stress test your affordability at a higher rate, typically 3% above your initial rate. This ensures you could still afford repayments if rates rise significantly after your fixed period ends.
Lenders also assess: Your gross annual income (most lend 4 to 4.5 times your income), your monthly outgoings, existing debts, credit history, and employment status.
The True Cost of Buying
Stamp Duty (SDLT/LBTT/LTT)
Stamp duty is a significant upfront cost. In England and Northern Ireland (from 1 April 2025):
- First £125,000 0%
- £125,001 to £250,000 2%
- £250,001 to £925,000 5%
- First-time buyers: 0% on first £300,000 (up to £500k properties)
Other Upfront Costs
Arrangement Fee
£500 – £1,500
Solicitor Fees
£1,000 – £2,000
Survey Fees
£400 – £1,000
Buildings Insurance
£150 – £400/yr
How Overpayments Can Save You Thousands
Making overpayments can dramatically reduce total interest and shorten your term.
Most lenders allow up to 10% overpayments per year without charges. Always check your ERC terms.
When to Remortgage
When your fixed or tracker deal ends, your mortgage automatically moves to the lender's SVR. As shown above, SVRs in 2026 are averaging over 7%, significantly higher than available deal rates. Sitting on an SVR even for a few months can cost hundreds of pounds you do not need to spend.
Most lenders allow you to lock in a new rate up to six months before your current deal expires, with the new rate activating at the changeover date. Start comparing deals and speak to a broker at least three to four months before your deal ends.