It shows how a higher mortgage rate changes the monthly repayment on the same loan amount and term. It does not model product fees, remortgage costs, lender stress tests or changes to the underlying deal structure.
RATE STRESS TEST
Mortgage rate rise calculator
New monthly repayment
£1,535
- Current payment
- £1,390
- Stress payment at 6.5%
- £1,688
- Monthly increase
- £146
The stress rate is the lender-style affordability test rate, which can be higher than the deal rate. That is why a mortgage can remain affordable on the current payment but fail under lender checks.
See how a small mortgage rate increase can affect your monthly payment, then compare the result with the main repayment and affordability tools. It is a practical way to judge whether the deal still works before remortgage or reset day arrives.
It shows how a higher mortgage rate changes the monthly repayment on the same loan amount and term. It does not model product fees, remortgage costs, lender stress tests or changes to the underlying deal structure.
If a borrower is comfortable at today’s rate, a small increase can quickly absorb the headroom that was left for bills or savings. This page is meant to show that pressure early, before the lender or fixed-term expiry forces the decision.
- The stress rate is the lender-style affordability test rate, which can be higher than the deal rate.
- A mortgage can remain affordable on the current payment but fail under lender checks.
How this fits the mortgage cluster
If the payment jumps too far, the next question is whether affordability still works, whether the term should be extended, or whether overpayments should be paused. This page is the stress-test layer that sits between the repayment calculator and the borrowing limit tools.
SOURCES & REVIEW
Checked against official guidance
Last reviewed 1 September 2026 · Rule version GB-2026.27.1
Daily/weekly source monitoring. If a source changes, the affected rule set is reviewed before publication.
All source links are kept visible so you can verify the figures used on this page.
Source line: Rate-rise assumptions are checked against MoneyHelper mortgage guidance and the shared affordability stress logic used across the site.
MoneyHelper: Mortgage rate changes ↗Sources, methodology and update policy →Report an issue or correction →WHY RESULTS DIFFER
Why two users can see different results
Why the result can differ
Different tax codes, payroll periods, Scottish bands, pension methods or lender assumptions can change the outcome.
One-off bonuses, pay frequency, overpayments, allowances and reliefs can move the result away from a simple annual estimate.
Where a rule depends on eligibility or legal status, this page shows an estimate and links to official guidance.
This section is intentionally repeated on key tools so the explanation stays near the result instead of being hidden in a separate policy page.
COMMON QUESTIONS
Frequently asked questions
When would my payment change?
It depends on whether your deal is fixed, variable or tracking a reference rate.
Does this include fees?
No. Product, arrangement and early repayment fees are excluded.
Why does a small rate change matter so much?
Because mortgage payments are long-term annuities, so even a small rate move is applied across the whole remaining term.
Does the stress rate equal my actual rate?
No. It is a lender-style affordability check and is often higher than the headline deal rate.
Should I use this before a remortgage?
Yes. It helps show whether the monthly budget still works if the new rate is higher than expected.