Buy-to-Let Stress Test Calculator
See the maximum loan a rental's rent supports at a given stress rate and interest cover ratio, or test a specific loan amount.
Buy-to-Let Stress Test Calculator
See the maximum loan a rental's rent supports at a given stress rate and interest cover ratio, or test a specific loan amount.
Lender notional rate, often around 5.5%, or the pay rate plus 2%.
Optional: enter a loan to test it; leave 0 to see the maximum.
Lenders vary the stress rate and the ICR required by product, tax band and whether the mortgage is personal or via a company. A 5-year fixed rate is often stressed at a lower rate than a variable deal. This is an estimate only, not a quote or an offer of finance.
How the buy-to-let stress test works
Before offering a buy-to-let mortgage, lenders check that the rent would still cover the interest payment at a higher notional rate, not just the rate you are actually paying. This protects against rates rising and against the loan being unaffordable if the true pay rate proves optimistic.
The check compares annual rent against annual interest at the stress rate, expressed as the interest cover ratio, or ICR. A lender might require 125% cover for a limited company or basic-rate taxpayer, and a higher 145% for an individual higher-rate taxpayer, because Section 24 leaves less of the rent available after tax.
The maximum loan a property supports is therefore driven by the rent, not just the property value or your deposit. A high-value property with modest rent can be stress-test constrained long before it reaches a normal loan-to-value limit.
Frequently asked questions
Why do lenders use a higher stress rate than the actual mortgage rate?
To check the rent would still cover the interest if rates rise, or if the pay rate on offer changes. It builds in a margin of safety rather than assuming today's rate holds for the whole term.
Why is the ICR higher for individual higher-rate taxpayers?
Because Section 24 restricts mortgage interest relief to a basic-rate credit for individual landlords, more of the rent is needed to cover tax as well as the mortgage, so lenders ask for a bigger buffer, often 145% rather than 125%.
Does passing the stress test mean the lender will offer the loan?
Not on its own. It shows the loan clears one common affordability hurdle. Lenders also assess the property, your income, credit history, deposit and their own criteria before making an offer.
Want to be sure of your position?
A calculator gives you the shape of the answer. We confirm your exact figure and the reliefs that apply to you. Tell us about your situation for a no-obligation review.