Buy-to-Let Mortgage Calculator UK 2026
Compare BTL affordability across 50+ UK buy-to-let lenders. Individual or limited company, basic or higher-rate tax — see exactly what each lender would offer in minutes. No credit search.
Start BTL CheckHow is buy-to-let affordability calculated?
BTL affordability is rental-led, not income-led. Lenders care about whether the property's rental income covers the mortgage interest at a stress rate, with a comfortable margin. The maths is the Interest Cover Ratio (ICR) — monthly rent ÷ monthly mortgage interest at the stress rate × 100%.
Different lenders set different ICR thresholds and different stress rates, which is why one lender will offer £200,000 on the same rental income that another caps at £160,000. Three numbers move the BTL borrowing picture most:
- ICR threshold — typically 125-145% for basic-rate taxpayers, 145-165% for higher-rate. Limited companies sit at 125-145% regardless of personal tax band.
- Stress rate — the “what if rates went up” rate the lender applies. 5-yr fixed products usually stress at the product rate (no headroom); shorter fixes stress at 5.5-7%.
- Maximum LTV — most BTL caps at 75-80%. 85% LTV is available but rates jump materially.
Should I buy in my own name or through a limited company?
Since the 2017 mortgage-interest tax-relief cap, higher-rate-taxpayer landlords have increasingly bought new BTL properties through a limited company (SPV) because mortgage interest is fully deductible against company profits — not capped at the 20% credit individuals get.
Trade-offs: limited-company products have slightly higher rates (typically 0.2-0.4% over equivalent personal BTL), and there's annual accountancy plus tax overhead. For basic-rate taxpayers the personal route is usually still cheaper. For higher-rate and additional-rate taxpayers, SPV is almost always more efficient on yields above ~5%.
The calculator runs both scenarios so you can compare what each route gets you on the same rental income.
Which UK lenders accept buy-to-let?
The BTL pool is around 50+ lenders ranging from high-street specialists (BM Solutions, The Mortgage Works, Accord, Skipton) through dedicated BTL brands (Paragon, Landbay, Fleet, CHL, Foundation, Keystone, Vida) to specialist limited-company players (Kent Reliance, Aldermore, Hodge, Interbay).
Each has a slightly different stance on first-time landlords, portfolio landlords, HMOs, holiday lets, ex-pats, foreign nationals, and limited-company structure. Our calculator filters lenders based on your profile and runs ICR + stress rate against each one.
What the BTL calculator checks
Property value & deposit
Maximum LTV per lender, plus first-time-landlord caps where they apply.
Rental income & ICR
Stress-tests your rental against each lender's ICR threshold and stress rate.
Personal income
Some lenders set a personal-income floor for BTL — checked per-lender.
Borrower type
Individual, limited company, ex-pat, foreign national, portfolio landlord — different lender pools.
BTL Mortgage FAQs
How does a buy-to-let mortgage calculator work?
BTL lenders use the Interest Cover Ratio (ICR) — your expected rental income divided by the mortgage interest at a stress rate. Most require ICR of 125-145% (basic-rate taxpayers) or 145-165% (higher-rate). Our calculator runs your figures against each lender's stress rate and ICR threshold to show what each would lend.
What rental income do BTL lenders need?
Lenders use the higher of (a) the rental valuation from your surveyor or (b) your declared market rent. As a rule of thumb, monthly rent needs to be 125-145% of the monthly mortgage interest at the lender's stress rate. Higher-rate taxpayers typically need 145-165% to satisfy the same lender.
Should I buy through a limited company?
Limited company BTL changes the maths because mortgage interest is fully deductible against company profits (vs the 20% credit cap for individuals). Most BTL lenders now have dedicated SPV (special purpose vehicle) products. Our calculator covers both individual and limited-company applications and compares lenders across both.
Do I need a deposit for buy-to-let?
Yes — most BTL lenders cap LTV at 75-80% (so a 20-25% deposit). A handful go to 85% but at materially higher rates. First-time landlords typically face slightly tighter LTVs.
What's the minimum income for a BTL mortgage?
Most BTL lenders require £25,000+ personal income (separate from the rental). A few accept lower with strong rental coverage. First-time landlords often face an income floor; portfolio landlords are usually exempt.
Are HMOs and holiday lets supported?
HMOs and holiday lets are specialist products with a smaller lender pool and slightly higher rates. Our calculator surfaces the lenders that accept each — but the calculator UI applies general BTL criteria; speak to a broker for HMO/HL specifics.
Ready to compare BTL lenders?
5 minutes. No credit search. Results from 50+ UK buy-to-let lenders.
Start BTL Check
