Buy-to-let stress tests (ICR) in 5 minutes: why rent can limit borrowing
A quick buy-to-let explainer: lenders often stress-test at a higher rate and require rent to cover stressed interest by an ICR percentage.
Published: 10/03/2026 • Last verified: 10/03/2026
The idea
Many buy-to-let lenders test affordability using:
- a stress rate (higher than the deal rate), and
- an ICR requirement (rent must exceed stressed interest by a %)
This is why your borrowing can be capped by rent, even with a big deposit.
A tiny example
If stressed monthly interest is £700 and the ICR requirement is 130%, the required rent is about:
£700 × 1.30 = £910/month
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