BTL Max Mortgage Calculator
The maximum buy-to-let mortgage your expected rent will support — under typical UK lender stress tests and rental coverage rules.
How the numbers land.
Three steps from input to a figure you can plan around.
Enter the rent
Expected monthly rent, deposit, the product rate, and the lender's stress rate (often 5.5% or pay-rate +2%).
See the ceiling
Maximum loan that meets the lender's ICR (interest cover ratio) at the stressed rate.
Match a lender
BTL lenders use different ICRs and stress rules. A broker matches the property's rent to the right lender.
Get a BTL quote
Key figures behind this calculator
125–145%
Required rental cover
5.5%+
Typical stress rate
25%
Minimum deposit
75%
Standard max LTV
What we assume.
Every calculator is a model. Here's where ours rounds, simplifies, or hands the detail to a real adviser.
Standard ICR ranges
Calculator uses 125% (basic-rate) and 145% (higher-rate) ICR. Limited-company BTL, HMO, and multi-unit lenders apply their own.
Stress rate is critical
A small stress-rate move can shift the maximum loan by tens of thousands. Confirm the rate the lender will use before offering.
No top-slicing
Some lenders use surplus personal income to bridge a rent shortfall. The figure here is rent-only.
No tax modelled
Section 24 limits mortgage interest relief to a 20% credit. Higher-rate landlords often need a larger surplus than the calculator implies.
Frequently asked.
Lenders apply an Interest Cover Ratio (ICR) — typically 125% for basic-rate taxpayers and 145% for higher-rate — at a stressed rate (often 5.5% or pay-rate +2%) to ensure your rent covers the mortgage with margin.
Still got a question we haven't answered?
Talk to an adviserFrom figure to offer.
Calculators give you a useful estimate. The real number depends on your full circumstances, credit profile, and the lender that ultimately approves the case. Our CeMAP-qualified advisers compare 90+ UK lenders and translate the btl max mortgage calculator into a deal you can actually take.
No-obligation chat
Book a call — we'll discuss your situation and what you're trying to achieve, no commitment.
Higher approval confidence
Our brokers know which lenders suit first-time buyers, remortgagers, buy-to-let, and complex cases.
Service that performs
Clear communication, realistic timelines, and the right product — not just the lowest headline rate.