Buy-to-Let Mortgage Calculator
Work out the monthly cost, gross yield and rent-cover on a UK buy-to-let purchase.
Typically ~1.5% higher than residential.
UK BTL deposits usually 25%+.
A £0 UK buy-to-let generating £0/month rent covers a £0 interest-only mortgage payment, leaving £0 gross monthly cashflow — a 0.00% gross yield.
How UK BTL mortgages work
Deposit & rate
Minimum 25% deposit on high-street BTLs; 40%+ unlocks sharp rates. BTL rates price ~1–2% above residential because of higher lender risk.
Rent cover (ICR)
Lenders stress rent against the mortgage — usually at 5.5% or pay rate + 2%. Need 125% for basic-rate taxpayers, 145% for higher-rate. See the BTL stress-test calculator.
Frequently asked questions
How much deposit do I need for a buy-to-let?
UK BTL lenders typically require a minimum 25% deposit (75% LTV). A 40% deposit unlocks the sharpest rates. Specialist lenders may accept 15–20% but at a rate premium.
Why are BTL mortgages interest-only?
Most BTLs are interest-only because it maximises tax-efficient cashflow and lenders underwrite on rent coverage, not capital repayment. The property sale typically repays the loan.
What is rent cover / ICR?
Interest Coverage Ratio — the ratio of rent to mortgage interest. Lenders require 125%+ for basic-rate taxpayers and 145%+ for higher-rate. Typically stress-tested at 5.5% or the pay rate + 2%.
What is a good BTL gross yield?
4–6% in London and the South East, 6–10% in the Midlands and North, 10%+ in specialist lets like HMOs. Gross yield ignores costs; net yield after costs is typically 2–3% lower.
Can I live in my BTL property?
No. Living in a BTL-mortgaged property breaches the terms and could be treated as mortgage fraud. You'd need to remortgage onto a residential product first (or a let-to-buy if the move is temporary).
Reviewed by the Mortgage118 editorial team. Net cashflow excludes tax, voids, management, insurance and maintenance. This calculator provides an estimate only and does not constitute mortgage advice.