Buy-to-Let Mortgage Calculator UK 2026
Compare BTL affordability across 21 UK buy-to-let lenders. Individual or limited company, basic or higher-rate tax — see an estimated maximum for each lender in about 5 minutes. No credit search. Last reviewed October 2026.
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 could lend £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% for basic-rate taxpayers, 145% for higher-rate (up to 165% for additional-rate at some lenders). Limited companies sit at 125-145% regardless of personal tax band.
- Stress rate — the “what if rates went up” rate the lender applies. It depends on the lender and the fix length, from about 4.5% to 10.5%. Two-year fixes get the toughest test, usually about 6–7.5% at today's pay rates and up to about 10.5% at some specialist lenders: many lenders use the higher of the pay rate plus 2% or 5.5%. Five-year fixes are usually tested at or near the pay rate, about 4.5–6% at most lenders. The calculator assumes a five-year fix unless you choose two years.
- Maximum LTV — most BTL caps at 75-80%. 85% LTV is available but rates jump materially.
Most buy-to-let mortgages are not regulated by the Financial Conduct Authority.
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 limited to the basic-rate credit individuals get (20% in 2026/27, rising to 24% from April 2027).
Trade-offs: limited-company products often have slightly higher rates than equivalent personal BTL, and there's annual accountancy plus tax overhead. Which route works out cheaper depends on your tax position, the yield and your plans for the property, so take advice from a qualified tax adviser before you decide.
To compare the two routes, run the calculator once as an individual and once as a limited company, with the same rental income.
Which UK lenders accept buy-to-let?
The wider UK BTL market has more than 80 lenders, from high-street brands (BM Solutions, The Mortgage Works, Accord, Skipton) and dozens of building societies, through dedicated BTL lenders (Paragon, Landbay, Fleet, CHL, Foundation, Keystone, Vida) to specialist limited-company lenders (Rely, Aldermore, 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 checks 21 buy-to-let lenders, running each one's ICR and stress rate against your rent. It covers standard buy-to-let for individuals and limited companies; HMOs, holiday lets, ex-pat and foreign-national lending aren't covered.
What the BTL calculator checks
Property value & deposit
Each lender's maximum LTV, applied to its figure.
Rental income & ICR
Stress-tests your rental against each lender's ICR threshold and stress rate.
Personal income
A few lenders top up the rent with your personal income; we include it where they do.
Borrower type
Individual or limited company. Each lender's ICR and tax-band rules are applied to the one you choose.
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% (basic-rate taxpayers) or 145% (higher-rate), with some lenders asking up to 165% for additional-rate taxpayers. Our calculator runs your figures against each lender's stress rate and ICR threshold to estimate what each could lend.
What rental income do BTL lenders need?
Lenders usually base the calculation on the surveyor's opinion of the market rent, not your own estimate. If a tenancy is already agreed, some lenders use the lower of the agreed rent and the surveyor's figure. Our calculator uses the rent you enter, so a lower surveyor's figure would mean a lower maximum. As a rule of thumb, monthly rent needs to be 125% of the monthly mortgage interest at the lender's stress rate for basic-rate taxpayers. Higher-rate taxpayers typically need 145%, and some lenders ask up to 165% for additional-rate taxpayers.
Should I buy through a limited company?
Limited company BTL changes the maths because mortgage interest is fully deductible against company profits (individuals only get a basic-rate tax credit: 20% in 2026/27, rising to 24% from April 2027, when their rental profits start being taxed at 24%, 44% or 49% in England, Wales and Northern Ireland). Most BTL lenders now have dedicated SPV (special purpose vehicle) products. Our calculator covers both individual and limited-company applications: choose one when you start, then run it again with the other to compare.
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?
There's no single rule. Some lenders set a minimum personal income outside the rent, typically £20,000–£25,000. For example, Barclays, HSBC and Santander ask for £25,000, Skipton for £20,000, and Paragon for £25,000 unless you already have four or more mortgaged buy-to-lets. Others set a floor only for first-time or newer landlords: Aldermore and Keystone ask for £25,000, and Landbay asks for £25,000 if you have under two years' experience. Many large BTL lenders, including The Mortgage Works, BM Solutions, NatWest, Coventry, Accord and Fleet, have no minimum income for standard BTL, though they still want your income declared and some want earned or pension income. Using your salary to cover a rent shortfall (top-slicing) usually needs a much higher income.
Are HMOs and holiday lets supported?
HMOs and holiday lets are specialist products with a smaller lender pool and slightly higher rates. Our calculator doesn't cover them: it applies standard buy-to-let criteria, so speak to a broker about HMO or holiday-let lending.
Ready to compare BTL lenders?
About 5 minutes. No credit search. Results from 21 UK buy-to-let lenders.
Start BTL Check