UK Mortgage Calculator
Estimate monthly mortgage costs for repayment or interest-only loans using UK-style inputs.
- Loan amount£0
- Loan-to-value (LTV)0%
- Estimated monthly payment£0
- Total paid over term£0
- Total interest£0
- Total including fees£0
This is an estimate and not financial advice. Actual payments depend on lender affordability rules, product terms, and future rate changes.
Why people search “mortgage calculator uk martin lewis”
Many UK homebuyers search for a mortgage calculator alongside Martin Lewis because they want clear, practical, money-saving guidance before speaking to a lender or broker. The goal is usually simple: understand monthly payments, compare options, and avoid taking on a mortgage that becomes stressful later.
A good calculator helps you answer the key questions quickly:
- How much will I pay per month?
- How much does my deposit reduce the payment?
- Is repayment or interest-only more realistic for my situation?
- What is the true long-term cost once interest and fees are included?
How this UK mortgage calculator works
1) Loan amount
Your loan amount is calculated as:
Property price − deposit = mortgage loan
If you buy at £300,000 and put down £45,000, your mortgage loan is £255,000.
2) LTV (Loan-to-Value)
LTV tells lenders how much risk they are taking. It is:
Loan amount ÷ property price × 100
Lower LTV mortgages often get better rates. For example, 60% LTV deals are usually cheaper than 90% LTV deals.
3) Monthly mortgage payment
For a repayment mortgage, your monthly payment covers both interest and part of the loan capital. Over time, your balance falls to zero by the end of the term (assuming you keep up payments).
For an interest-only mortgage, you pay only interest each month, so monthly cost can look lower, but the original loan still needs to be repaid at the end of the term.
Repayment vs interest-only: a practical UK view
Repayment mortgage
- Higher monthly payments than interest-only (usually).
- Builds equity gradually.
- Loan is designed to be fully repaid at term end.
Interest-only mortgage
- Lower monthly payment now.
- Loan balance does not reduce unless you overpay capital.
- You must repay the full loan later (sale of property, investments, other plan).
What this calculator does not include automatically
To keep this tool quick and clear, it focuses on core mortgage maths. Your real housing budget should also include:
- Stamp Duty (if applicable under current UK bands)
- Conveyancing and survey fees
- Broker fees (if charged)
- Buildings insurance and possibly life cover
- Service charge and ground rent (leasehold)
- Maintenance costs and emergency savings
How to use this calculator intelligently
Test multiple rate scenarios
Try your current rate, then test +1% and +2%. This helps you see whether your budget still works if fixed terms end and refinance costs rise.
Try shorter and longer terms
A longer term reduces monthly payments, but increases total interest. A shorter term usually does the opposite. If affordability allows, a shorter term can save a lot over decades.
Look at total cost, not just monthly cost
Many borrowers naturally focus on monthly affordability, but the total paid figure is where long-term savings appear. Tiny rate differences can add up to big money over 20 to 35 years.
Quick first-time buyer checklist (UK)
- Build deposit and emergency fund separately.
- Check your credit reports and fix errors early.
- Avoid taking large new debt before applying.
- Get an agreement in principle to understand your borrowing range.
- Compare total mortgage cost including fees, not just headline rate.
Example scenario
Suppose you are buying a £280,000 home with a £28,000 deposit (10%), at 5.1% over 30 years:
- Loan amount: £252,000
- LTV: 90%
- Repayment monthly cost: higher than interest-only, but balance shrinks over time
- Total paid over full term: significantly above the borrowed amount due to interest
If you increase the deposit to £56,000 (20%), your LTV drops to 80%. That may unlock better rates and lower monthly payments immediately, plus less total interest.
Final thoughts
If you came here searching for a “mortgage calculator uk martin lewis,” you are likely trying to make a careful, informed decision. That is exactly the right approach. Use this calculator to build confidence, compare scenarios, and stress-test your budget. Then confirm options with a regulated mortgage adviser or lender before committing.
The smartest mortgage is usually one that is both affordable now and resilient if life changes later.