4.97 out of 5 based on 2,400+ reviews

ICR Stress Rate Calculator

Enter the mortgage amount, rental income, ICR requirement, and stress rate to calculate the maximum loan supported by rent.

Rated 4.97 out of 5 from 2,400+ reviews

Inputs

£
£
%
%
ICR = Interest Coverage Ratio
A lender affordability measure comparing rental income against stressed mortgage interest payments. Rental income defaults to monthly rent, but you can switch it to annual. Stress rate is used for affordability testing.

ICR / Stress-Rate Matrix

Rows are ICR requirements. Columns are mortgage stress rates from 3.00% to 7.00% in 25 bps increments.

Supports entered mortgage amount Below entered mortgage amount

This calculator is for indicative affordability only. It does not replace lender criteria, advice, underwriting, fees or product-specific affordability rules.

How This Calculator Works

This tool shows you the maximum mortgage a lender is likely to offer based on the rent a property generates, using the same method lenders apply when assessing buy-to-let affordability.
Enter the mortgage amount you’re requesting, the expected rental income (monthly or annual), the lender’s Interest Coverage Ratio (ICR) requirement, and the mortgage stress rate. The calculator then works out:

Why ICR And Stress Testing Matter

Interest Coverage Ratio is one of the key hurdles in any buy-to-let mortgage application. Rather than assessing affordability the way a residential mortgage does — against the borrower’s income — lenders instead test whether the rental income itself would comfortably cover the mortgage interest, even if rates were higher than they are today.
That “even if rates were higher” element is the stress rate: a deliberately cautious interest rate used purely for the affordability calculation, not the rate you’ll actually pay.

A mortgage affordability test is a calculation made by the lender to determine how much they are willing to let you borrow for a mortgage.

The reason this matters is that ICR and stress rate requirements vary significantly between lenders, and even between products from the same lender.

A basic-rate taxpayer applying for a standard buy-to-let might face a 125% ICR at a 5.5% stress rate, while a limited company or higher-rate taxpayer applicant could see different thresholds applied. Even small differences here — a few percentage points on the stress rate, or 10% on the ICR — can significantly change the maximum loan a property will support, sometimes by tens of thousands of pounds.
This is why two investors with identical properties, rents, and deposits can end up with very different borrowing outcomes depending on which lender and product they apply through.

It’s also why relying on a single lender’s criteria — or a generic online estimate — can understate what’s actually achievable. An adviser with access to a wide panel of lenders can identify which products apply more favourable ICR or stress rate assumptions to your specific circumstances, which is often the difference between a mortgage application passing comfortably or falling short.

Important Information

The above calculations are only examples and are not guaranteed. Loans are subject to status and valuation and are not available to persons under 18 years of age. Written quotations available from individual lenders. For secured loans the lender will require a charge on your property and in the case of endowment mortgages, an endowment/life policy for the amount of the advance and a charge over the property. For interest only mortgages, the above calculations do not take into account the cost of any endowment, pension or other savings plan being used to repay the loan. In addition, the figures shown in respect of both repayment and interest only mortgages do not include the cost of additional life cover.

All mortgages are subject to the applicant(s) meeting the eligibility criteria of lenders. Loans are subject to status and valuation and are not available to persons under 18 years of age. Written quotations are available from individual lenders. For secured loans, the lender will require a charge on your property and in the case of endowment mortgages, an endowment/life policy for the amount of the advance and a charge over the property. For interest-only mortgages, the above calculations do not take into account the cost of any endowment, pension, or other savings plan being used to repay the loan. In addition, the figures shown in respect to both repayment and interest-only mortgages do not include the cost of additional life cover. Your home or property may be repossessed if you do not keep up repayments on your mortgage.

The Financial Conduct Authority does not regulate some forms of buy-to-let mortgage. This information does not contain all of the details you need to choose a mortgage.The information provided by these calculators is for illustrative purposes only and does not constitute a mortgage offer, decision in principle or mortgage advice.

Bespoke Mortgage Requirements?

Whatever your situation, our premier mortgage team can advise on suitable solutions. We specialise in complex and bespoke mortgage solutions to help you find competitive terms.

Comparing over 300 lenders
Free initial consultation with no obligation to proceed
25+ years of industry experience and relationships