Enter the mortgage amount, fixed rate, fixed period, product fee, follow-on rate, and overpayment for each deal to compare cash paid and balance over time.
Quick read
Full-term winner
Mortgage B
£21,479 total cost difference over the modelled mortgage terms.
This estimate models one fixed-rate period followed by one follow-on rate. It does not include remortgaging, incentives, valuation costs, or early repayment charges.
Adviser report
Build a print-friendly pack with the figures entered, main results, assumptions, caveats, and next discussion points. Nothing is saved and no PDF is generated on the server.
Estimate
Estimated better fit: Mortgage B
Mortgage B looks stronger on the modelled numbers.
Inputs
Estimate
Estimated better fit
Mortgage B
Mortgage B looks stronger on the modelled numbers.
Winner over initial fix
Mortgage A
Lower amount paid by each fix end.
Winner over full term
Mortgage B
Lower total paid over the full mortgage.
Lower balance after fix
Mortgage B
Useful when deciding what happens next.
Monthly payment difference
£42
Total cost difference
£21,479
Cost during fix difference
£47,991
Remaining balance after fix difference
£20,145
Result interpretation
First-time buyer guide
Lowest monthly payment is not always the cheapest mortgage. Use the monthly payment, fees, remaining balance, follow-on rate, LTV, and product rules together before treating one deal as better.
The interest rate you pay for the initial deal period, such as 2 or 5 years.
Why this matters
It strongly affects the monthly payment while the fix lasts.
Common misunderstanding
A lower fixed rate can still cost more if fees, term, or balance after the fix are worse.
The total time used to repay the mortgage, often 25 to 35 years for a first-time buyer.
Why this matters
A longer term can reduce monthly payments but usually increases total interest.
Common misunderstanding
Choosing the lowest monthly payment does not automatically mean choosing the cheapest mortgage.
The rate used after the fixed period ends if you do not remortgage or switch product.
Why this matters
It can change the comparison if one deal looks cheap during the fix but expensive afterwards.
Common misunderstanding
Many buyers compare only the fixed period and forget what happens after it ends.
A lender fee for taking the mortgage product, paid upfront or added to the mortgage.
Why this matters
A low rate with a high fee may not beat a slightly higher rate with a lower fee.
Common misunderstanding
Adding the fee to the mortgage is not free; it can increase the balance and interest.
An early repayment charge may apply if you repay, overpay too much, or leave the deal early.
Why this matters
It can affect whether a deal is flexible enough if you sell, overpay, or remortgage early.
Common misunderstanding
This comparison does not model ERCs, so check the product rules separately.
Loan-to-value compares the mortgage amount with the property value.
Why this matters
LTV bands can affect which rates you qualify for and how much deposit is needed.
Common misunderstanding
A small change in deposit or property value can move the deal into a different LTV band.
Lowest monthly payment check
Lowest monthly payment is not always the cheapest mortgage because fees, rate changes, term length, and the balance left after the fix can move the true cost.
Use these numbers next
Use these Mortgage B figures as a planning snapshot if this is the scenario you want to visualise in the dashboard next.
Continue to plan ownershipConfidence check
Use this checklist to spot planning gaps before you move from calculator estimates to conversations with lenders, brokers, or conveyancers. This is educational only and is not financial advice.
Keep emergency savings separate from the deposit and completion costs before treating a purchase budget as comfortable.
Review buying costsBudget for removals, legal work, surveys, mortgage fees, insurance, utilities, and immediate setup costs after completion.
Check upfront cost mathsAn Agreement in Principle can help you understand whether a lender may consider your application before you make an offer.
Plan your mortgage stepsIncome, credit history, deposit source, employment type, property type, and existing commitments can all affect lender decisions.
Understand affordabilitySense-check the property value, deposit, mortgage amount, rate, fees, term, and monthly payment against current quotes before relying on the estimate.
Review comparison assumptionsAssumptions
Check these inputs before relying on the result.
Last reviewed
12 June 2026
Interest method
Monthly interest is estimated from the annual rate unless a page states a different method. Lender figures can use daily interest, product-specific rules, and exact payment dates.
Educational scope
UK-focused calculator estimate. It explains trade-offs and does not make a personal recommendation.
Results are estimates based on the assumptions shown here. They are not financial advice and can differ from lender figures because real products, fees, rate changes, overpayment rules, and repayment timing vary.
Learn the comparison maths
Follow a plain-English lesson covering fixed rates, product fees, follow-on rates, total borrowing costs, and a worked two-mortgage comparison.
Open the comparison lessonRecommendation summary
Estimated better fit
Mortgage B
Mortgage B looks stronger on the modelled numbers.
During the fix
Mortgage A is lower
Difference: £47,991
Over the full term
Mortgage B is lower
Difference: £21,479
Monthly pressure
Mortgage B is lower
Difference: £42
Balance after fix
Mortgage B is lower
Difference: £20,145
The fixed-period winner and full-term winner differ. That usually means your remortgage plan matters: compare the period you expect to keep the deal, not only the headline monthly payment.
Mortgage A
Monthly during fix
£1,390
Cost during fix
£34,349
Balance after fix
£238,669
Total interest
£243,842
Mortgage B
Monthly during fix
£1,347
Cost during fix
£82,340
Balance after fix
£218,524
Total interest
£221,863
Visual comparison
The line charts compare cumulative amount paid and remaining balance at yearly intervals. The exact numbers are also summarised in the cards and table below.
Lower balances can matter if you expect to remortgage, move, or make further overpayment decisions after the fixed period.
Compare
Recommended next steps
A short follow-up can help put this estimate into context before you make a money decision.
This calculator provides estimates only and does not constitute mortgage or financial advice. It assumes repayment mortgages, one fixed-rate period, one follow-on rate, and constant overpayments. Your lender offer may include other costs, incentives, early repayment charges, or restrictions.
Learn This Calculation
Use the education page before relying on the result. It explains the assumptions, shows the maths, gives worked examples, and includes practice questions so the estimate is easier to check.
Learn why the lowest monthly payment is not always the lowest-cost mortgage.
Covers fixed-rate payments, product fees, balances after a fix, follow-on rates, and total modelled cost.
Works through two deals with different fees and follow-on rates to expose the trade-off.
Practise comparing two deals over the fixed period and across the full term.
Next Lesson
If you already have a mortgage, compare staying put with switching after fees and ERCs.