Buy-to-let remains one of the most actively pursued property strategies in the UK. In 2026, landlords at every level, from those managing a single rental flat to those overseeing multi-property portfolios, are navigating a market that looks quite different from five years ago. Mortgage rates, stamp duty rules, lender criteria, and the tax landscape have all shifted in ways that change the calculations considerably. This guide covers what you need to know before applying for a buy-to-let mortgage in 2026, whether you are starting out or looking to expand what you already hold.
Key Takeaways
- Buy-to-let mortgages are assessed primarily on rental income rather than personal earnings, using a measure called the Interest Coverage Ratio (ICR).
- A minimum deposit of 25% is required by most lenders; a 40% deposit typically opens access to the most competitive rates.
- A 5% stamp duty surcharge applies to all buy-to-let purchases in England and Northern Ireland on top of standard rates, with Scotland and Wales carrying their own equivalent levies.
- If you own four or more mortgaged buy-to-let properties, you are classified as a portfolio landlord, which triggers a more detailed underwriting process.
- Purchasing through a limited company or SPV can offer tax advantages but involves higher mortgage rates and additional administration.
- Borrowers with complex income are often better served by specialist lenders using manual underwriting rather than automated assessment systems.
- A whole-of-market broker gives access to lenders who do not deal with the public directly, often where the strongest options for non-standard applications sit.
Is Buy-to-Let Still Worth It in 2026?
Rental demand across the UK remains strong. A shortage of rental stock, consistently high tenant demand, and low vacancy rates have kept rents rising across most of the country. Gross yields of 5% to 8% are achievable in many areas, particularly outside London and the Southeast.
The financial picture has shifted. Mortgage rates remain higher than the sub-2% products many landlords locked into before 2022. The restriction of mortgage interest relief under Section 24 of the Finance Act 2015 is now fully in effect, meaning higher-rate taxpayers holding property in their personal name pay income tax on rental income before deducting mortgage interest costs. Buy-to-let still works, but the structure of how you hold the property has become a genuine decision rather than an afterthought.
Buy-to-Let vs Residential: The Difference
Buy-to-let and residential mortgages are separate products, assessed differently by different lenders, under different criteria.
A residential mortgage is built around your personal income and your capacity to service the debt each month. A buy-to-let mortgage is built around the property itself, specifically the rental income it can generate and whether that income is sufficient to cover the mortgage.
This distinction flows through everything. The rates are higher. The deposit requirements are greater. The affordability calculation is entirely different. And the regulatory framework differs as well: most buy-to-let mortgages fall outside FCA regulation, with one exception being regulated buy-to-let products, which apply when a property is let to a close family member.
Deposits and Loan-to-Value
Most buy-to-let lenders set a minimum deposit of 25%, allowing you to borrow up to 75% of the property's value. At this level, you can access the market, but the rates available reflect the higher loan-to-value ratio, and not all lenders will participate.
At 40% deposit, the picture changes. The 60% LTV threshold is where the most competitive rates become available, and for borrowers who can reach it, the difference in both monthly payment and total borrowing cost over the mortgage term is meaningful.
For purchases through a limited company or special purpose vehicle, minimum deposit requirements vary by lender. Most require at least 25%, with some setting the bar higher depending on the borrower's profile and company structure.
How Lenders Assess Affordability: The ICR Explained
The Interest Coverage Ratio is the central affordability test for buy-to-let lending. It measures whether a property's expected rental income is sufficient to cover the cost of the mortgage interest, with a buffer built in to protect both lender and borrower if conditions change.
Lenders require rental income to cover between 125% and 145% of the monthly mortgage interest, calculated at a stressed rate (typically 5.5% to 6%) rather than the actual rate on the mortgage. Higher-rate taxpayers in a personal name are usually assessed at 145%; basic rate taxpayers at 125%; limited company applications at 125%.
When rental income falls short, a larger deposit is usually the most practical fix. Reducing the loan amount reduces the interest that rental income needs to cover.
Stamp Duty on a Buy-to-Let Property
Every buy-to-let purchase in England and Northern Ireland carries a 5% additional stamp duty surcharge on top of standard residential rates. Scotland has its own Additional Dwelling Supplement, currently set at 8%. Wales applies a higher rate of Land Transaction Tax on additional properties. The combined bill across all of these can be considerably higher than many buyers anticipate, particularly in the mid-range price bracket.
One point worth planning around: stamp duty cannot be added to the mortgage. The full amount is payable in cash within 14 days of completion. It needs to sit in your available funds before you commit to a purchase, not as a figure to revisit afterwards.
Limited Company and SPV Structures
More lenders now offer buy-to-let products for company purchases, and rates have become more competitive, though they remain slightly higher than personal name equivalents. Our buy-to-let mortgages page covers company and SPV lending in more detail.
The appeal centres on tax treatment. Within a company, mortgage interest is fully deductible against rental income, unlike the restricted relief available to individuals under Section 24. Rental profits are subject to corporation tax rather than income tax, which for many landlords produces a more efficient overall position.
The trade-offs are real. Company mortgages carry higher rates, require more administration, and typically demand a personal guarantee from the director. Independent tax advice from a qualified accountant should always come before any structural decision is made.
Portfolio Landlords
Four or more mortgaged buy-to-let properties triggers a portfolio landlord classification. This does not prevent borrowing, but it changes how applications are handled, and being unprepared for that shift is one of the more common reasons portfolio applications stall.
Where a standard buy-to-let application focuses on the new property, a portfolio application requires the lender to review everything you hold: every property, its outstanding mortgage balance, its rental income, and how the new purchase fits into the overall picture. This is called a portfolio stress test, and it assesses whether your portfolio as a whole remains financially sound after the new purchase completes.
High street lenders can be conservative here, and some will not take on portfolio landlords at all. Specialist lenders are generally more experienced with these applications, more willing to look at the full picture in context, and more pragmatic in how they reach a decision. Approaching the right lender from the outset, rather than working through rejections, makes a real practical difference.
Complex Income and Buy-to-Let
Because buy-to-let affordability centres on rental income rather than personal earnings, the process can actually be more accessible for borrowers whose income does not follow a standard format. The ICR calculation does not change based on how you earn.
Income does still feature in the assessment, however. Lenders look at personal earnings when considering background affordability, covering void periods, maintenance costs, and existing commitments. This is where borrowers with complex income can run into difficulty.
- Dental professionals trading as a sole trader or via a limited company may find that automated lender systems struggle to process mixed NHS and private income accurately. Our article on navigating complex dental income beyond PAYE explains how specialist lenders assess this in full.
- Business owners who pay themselves through salary and dividends often find that high street lenders only count the salary figure, significantly understating their real income. Our guide to mortgages for company directors explains how manual underwriting handles this differently.
- Corporate executives with bonuses, long-term incentive plans, or car allowances frequently find these income components excluded from automated assessments altogether. Our corporate executive mortgage page sets out how we approach these cases.
What to Prepare Before You Apply
Have the following ready before your application goes in:
- Last three months' payslips and two to three years' P60s (PAYE applicants), plus evidence of bonuses or commission where relevant
- SA302 tax calculations and Tax Year Overviews for the last two to three years (sole traders), and an accountant's reference where the lender requires it
- Certified accounts, SA302 tax calculations, and confirmation of salary and dividend drawings for the last two to three years (limited company applicants)
- A rental income assessment from a RICS-qualified letting agent for a new purchase, or a current tenancy agreement and rental history for an established let
- A full portfolio schedule covering all properties, outstanding mortgage balances, and monthly rental income (portfolio landlords only)
How Sarah Grace Mortgages Can Help
Buy-to-let applications are rarely as simple as they first appear. The right product, lender, and structure all depend on your circumstances, and getting any one of these wrong can cost both time and money.
With over 30 years of experience, we have access to the full mortgage market, including lenders who work exclusively through brokers. We review your complete financial position before approaching anyone and structure the application to give it the strongest possible chance. Get in touch to find out more.
Frequently Asked Questions
Do I need a specific mortgage for a buy-to-let property?
Yes. A standard residential mortgage cannot be used for a property you intend to let out. Buy-to-let requires its own mortgage product, assessed on different criteria and sourced from lenders who operate in this part of the market.
Can I use equity from an existing property to fund the deposit?
Yes. Equity can be released through a remortgage or further advance on a property you already own and used as a deposit. Both lenders will need to be aware of this arrangement, as it affects your overall debt position.
What is the minimum deposit for a buy-to-let mortgage?
Most lenders require 25%. Some will consider less, but the range of products and lenders available narrows considerably below that level. A 40% deposit gives access to the most competitive rates.
How is rental income assessed for affordability?
Through the Interest Coverage Ratio (ICR). Rental income must cover 125% to 145% of the monthly mortgage interest, calculated at a stressed rate of around 5.5% to 6%. If the figure falls short, a larger deposit is usually the most practical fix.
Do I pay the stamp duty surcharge on a buy-to-let?
Yes. The 5% additional dwelling supplement applies to all buy-to-let purchases in England and Northern Ireland. Scotland and Wales have equivalent charges. The full amount is due in cash within 14 days of completion and cannot be added to the mortgage.
Is a limited company buy-to-let mortgage harder to get?
Not necessarily harder, but it involves a different set of lenders. The number offering company buy-to-let products has grown, and rates have become more competitive. A broker with experience in this area will know which lenders to approach.
I am a business owner. Will lenders count my dividends?
Many standard lenders will not, or will count only a proportion. Specialist lenders with manual underwriting can take a broader view, assessing the full income picture.
What is a portfolio landlord and how does it affect my application?
Four or more mortgaged buy-to-let properties triggers a portfolio landlord classification. Lenders then review your entire portfolio rather than just the new property. Specialist lenders are generally better equipped for these assessments than high street banks.
Do I need a broker for a buy-to-let mortgage?
You are not required to use one, but a significant number of buy-to-let lenders only deal through brokers. A whole-of-market broker gives access to the full market, often including more competitive rates and more flexible criteria than direct applications allow.
Important information
Your home may be repossessed if you do not keep up repayments on your mortgage.
This article provides general information only and does not constitute financial advice. All mortgage applications are subject to status, valuation, lender criteria and individual circumstances.
The Financial Conduct Authority does not regulate most forms of commercial buy-to-let mortgages or mortgages to limited companies.
Sarah Grace Mortgages Limited is authorised and regulated by the Financial Conduct Authority and is registered in England and Wales. Registered Number 09839864.
