BTL Stress Test (ICR) Calculator
Work out the minimum rent your UK buy-to-let needs to pass the lender's Interest Coverage Ratio (ICR) test.
Higher of 5.5% or pay rate + 2%.
125% basic-rate, 145% higher-rate.
A £0 UK buy-to-let stress-tested at 0% with a 0% Interest Coverage Ratio requires a minimum £0 monthly rent to pass the lender's affordability check.
How the ICR test works
The formula
Rent ≥ stressed interest × ICR%. Example: £200k loan at 5.5% = £917/month interest. 145% ICR means rent must be at least £1,329/month.
Ways to pass
- Bigger deposit → smaller loan → lower stress interest
- 5-year fix (often stressed at pay rate)
- Limited company SPV (often 125% ICR for any tax band)
- Specialist lender with lower ICR
Frequently asked questions
What is ICR?
Interest Coverage Ratio — the ratio of rental income to mortgage interest. UK BTL lenders require 125%+ for basic-rate taxpayers and 145%+ for higher-rate taxpayers.
Why is the stress rate higher than the pay rate?
Lenders stress rent against a higher notional rate to check affordability if rates rise. Typical stress: higher of 5.5% or pay rate + 2%. Five-year fixes may be stress-tested at the pay rate.
Do limited company BTLs have easier stress tests?
Often yes. Many lenders apply a 125% ICR to SPV/Ltd Co BTLs regardless of taxpayer status, because mortgage interest is fully tax-deductible inside a company.
What if my rent doesn't pass the stress test?
Options: bigger deposit (lower LTV), lower-rate product (lower stress payment), 5-year fix (may stress at pay rate), limited company structure, or a lender with lower ICR (some specialist lenders at 100–110%).
Does the stress test apply to remortgages?
Yes — most lenders re-run the stress test at application, though some offer simplified product transfers without re-testing if you stay with the same lender.
Reviewed by the Mortgage118 editorial team. Individual lender ICR and stress rules vary. This calculator provides an estimate only and does not constitute mortgage advice.