Mortgage Affordability Calculator for BTL
Written by Scott Jones, founder of PropertyKiln · Last updated
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1 min read
Reviewed Apr 2026
UK-wide
BTL lenders use an Interest Cover Ratio (ICR) rather than an income multiple. They want your rent to cover the mortgage interest at a "stress rate" (typically 5-6%) by 125% for basic-rate, 145% for higher-rate or limited company borrowers.
Enter the property value, rent, product interest rate, and your tax position. The calculator applies the relevant ICR and stress rate to show the maximum loan you could raise — which is often lower than you'd expect.
Use this before viewing properties. Knowing your real BTL borrowing ceiling saves you weeks on deals that won't complete.
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