Continue your plan
Useful next calculations
When to use this calculator
- Before comparing mortgage products, brokers or repayment types.
- When you want to test how a different deposit, rate or term changes the payment.
- When you need a quick estimate before using a formal illustration or agreement in principle.
- When you are stress-testing your budget against a higher rate.
A realistic UK planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
| Input | Value |
|---|---|
| Mortgage balance (£) | £200,000 |
| Current rate (%) | 5% |
| Rate to test at deal end (%) | 5% |
After entering these figures, review mortgage balance, current rate and tested rate together rather than in isolation. Then rerun the tool with one input adjusted.
How to read your results
Mortgage Balance
The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.
Current Rate
The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.
Tested Rate
The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.
Method & assumptionsAuthoritative sources
This mortgage rate-shock planner carries an entered balance forward to the end of the current deal, using the current rate and remaining term. It then recalculates the payment at a rate you enter and a separate higher stress rate.
The monthly housing budget you enter is compared with both future payment scenarios to make any headroom or shortfall clear. It is a planning estimate, not a lending decision.
It does not predict rates, compare live products, account for fees, model lender affordability criteria or include non-mortgage home costs. Use current lender illustrations and regulated mortgage advice where appropriate.
Common mistakes
- !Mixing up loan amount and property value, which can distort affordability and LTV.
- !Using a headline rate but forgetting fees, insurance, taxes or repayment type.
- !Testing only one term length instead of comparing the payment and total cost together.
- !Forgetting that a repayment mortgage and an interest-only mortgage produce very different monthly figures.
What to do next
- Run a second scenario with a higher rate or shorter term so you can see the downside clearly.
- Compare the result with an affordability or overpayment calculator before applying.
- Note the monthly payment and total interest for your strongest scenarios before you speak to a broker.
- Check whether a modest overpayment would reduce total interest — use the overpayment calculator next.
Frequently asked
Use arrow keys to navigate items, Enter or Space to expand/collapse.