Understanding ICR (Interest Coverage Ratio) for UK landlords

ICR — Interest Coverage Ratio — is the single most important number a UK BTL lender looks at. It decides whether they'll lend, how much, and at what rate. And yet most landlords either don't calculate it before applying, or calculate it wrong.

It's a simple ratio with three subtle parts. Get it wrong and you waste application fees, broker time, and weeks of negotiation on a deal that was never going to clear.

The formula

ICR = (Annual Rent) ÷ (Annual Mortgage Interest at Stress Rate)

Worked example. £200,000 property at 75% LTV → £150,000 loan. Lender stresses at 7% (because the product is 5%, plus 2%). Annual stressed interest = £150,000 × 0.07 = £10,500. Annual rent = £14,400 (i.e. £1,200/month). ICR = £14,400 ÷ £10,500 = 137%. (At current best-buy rates — a 4.5% 5-year product stressed to a 6.5% floor — the stressed interest would be £150,000 × 0.065 = £9,750, giving an ICR of 148%.)

If the lender requires 145% ICR, this fails by 8%. If they require 125%, it passes comfortably.

Why the stress rate is higher than your actual rate

This is where most landlords get caught out. Your product rate might be 5.0%, but the lender doesn't calculate ICR at 5.0%. They use a stress rate, designed to test whether the rent will still cover the loan if rates rise.

Standard formula: stress rate = higher of (a) 5.5% floor or (b) product rate + 2%.

• 5-year fix at 4.5% → stressed at 5.5% (the floor binds)
• 5-year fix at 5.0% → stressed at 7.0% (product + 2%)
• 2-year fix at 4.8% → stressed at 6.8%
• Some lenders use the product rate flat (no +2%) for 5-year+ fixes

The implication: the lower your product rate, the smaller the gap between rate and stress rate, and the easier ICR is to pass. A high product rate AND a high stress rate is the worst combination — typical of 2-year fixes today.

The thresholds: what lenders actually require

ICR thresholds vary by borrower profile:

• Limited company landlords: 125% — most generous. Reflects the corporate tax structure preserving net rental income better than personal taxation.
• Basic-rate (20%) individual taxpayers: 125-140% — depends on lender.
• Higher-rate (40%) individual taxpayers: 145% — the standard for most mainstream BTL lenders since Section 24 phased in. Tighter because Section 24 disallowed mortgage interest as a deductible expense (replacing it with a 20% basic-rate tax credit on finance costs), so higher-rate landlords pay more income tax on the same rent and need more rental cover to break even after tax. From April 2027 the basic-rate ICR threshold rationale still holds — the credit rises to 22% to match the new 22% property basic rate, so lenders are unlikely to relax the 145% bar.
• Portfolio landlords (4+ mortgaged properties): 145%-160% — sometimes stress-tested across the whole portfolio, not just the new property.
• HMO / Holiday let / Multi-unit freehold: 155-170% — higher because income is more volatile.

How to pre-qualify any deal in 60 seconds

Before you apply for a mortgage on any property, run this check:

1. Loan amount = property price × LTV (typically 0.75)
2. Stress rate = higher of 5.5% or (product rate + 2%)
3. Annual stressed interest = loan × stress rate
4. ICR = annual rent ÷ annual stressed interest
5. Compare to your lender's requirement (assume 145% if you're a higher-rate taxpayer unless you know otherwise)

If the result is below your lender's threshold, the application won't pass — change LTV, find a lender with lower ICR, or move on.

Three common ICR mistakes

• Calculating ICR at the product rate, not the stress rate.A deal that shows 145% ICR at 5% product rate might be 110% at the lender's 7% stress rate. The latter is what they care about.
• Using gross rent without occupancy adjustment. Lenders use achievable gross rent, but if your local void rate is 4-6 weeks they may haircut. Always model conservatively.
• Forgetting the higher threshold for higher-rate taxpayers.If you're a higher-rate income tax payer, mainstream lenders require 145%, not 125%. Plan for the stricter test.

How ICR shapes BTL strategy

Once you understand ICR, several strategy decisions become clearer:

• Limited company structureisn't just a tax decision — it's also a lending decision. The 125% threshold opens up deals that fail at the 145% personal threshold.
• Lower LTV unlocks worse-yielding properties. 65% LTV with 5.5% stress = ~3.6% interest cost on the property value. Even modest yields pass ICR easily.
• HMOs require materially higher gross yields than standard BTL because the ICR thresholds are higher.

How PropQuant computes this for you

PropQuant computes ICR on every BTL/HMO/SA deal automatically, alongside your other return metrics. The verdict engine flags deals that fail typical lender thresholds before you waste time applying. The stress test panel shows ICR at multiple rate stress levels so you can see how much cushion you have.

Frequently asked questions