Buy-to-Let Mortgage Guide for UK Landlords

Why we wrote this

We kept sending people links to bits of an answer.

Someone would ask how much they could borrow on a buy to let, and we would send one page. Then they would ask whether to buy it in a limited company, and we would send another, usually written by an accountant for accountants. Then they would ask what the rules actually are now that Section 21 has gone, and there was nothing good to send at all, because most buy to let guides still describe a market that stopped existing in May.

So this is the whole thing in one place. It covers how buy to let mortgages work, what lenders test and why, how the structural decisions interact, and the compliance calendar every landlord is now operating inside whether they have read it or not.

It is a guide, not a recommendation. Nothing here is advice about your situation, and there are no product rates in it, deliberately. What you will get is a clear picture of how the decisions connect, so that when you do talk to a broker you already know which questions matter.

Hiten Ganatra, Director at Visionary Finance, comments:

“Most landlords I meet are not short of information. However there is so much information out there that it has become too noisy and sometimes hard to distinguish what is current and what isn’t. A lot of what is currently online about buy to let has been written before the rules changed.”

1. What a buy to let mortgage actually is

A buy to let mortgage is a loan secured on a property you intend to rent out rather than live in. That sounds obvious, and it is, but almost everything that makes buy to let different from residential borrowing follows from it.

It is assessed on the rent, not your salary

A residential lender asks what you earn and works out what you can afford from that. A buy to let lender asks what the property will rent for and works out what the rent can support. Your income still matters, because most lenders set a minimum and because your tax position feeds the calculation, but the rent is the engine.

It is usually interest only

The large majority of buy to let lending is written on interest only terms, where you pay the interest each month and the capital is repaid at the end, normally from a sale or a refinance. That improves monthly cashflow and it is how most landlords run a portfolio. It also means you need a credible plan for repaying the capital, and lenders increasingly ask what it is.

Most of it is not FCA regulated

Ordinary buy to let lending to a landlord who chose to become a landlord is not a regulated mortgage contract. The Financial Conduct Authority does not regulate most buy to let mortgages. There is an important exception, sometimes called consumer buy to let, which covers people who did not set out to be landlords, most often someone who inherited a property or is letting a former home. That is regulated, and the protections and the process differ.

This matters more than most guides let on. If you are an accidental landlord, say so early, because it changes which lenders can help and what they have to do.

How much can you borrow: the rental stress test

This is the part that surprises people most often, and it is the single most useful thing to understand before you make an offer on anything.

A lender does not ask whether the rent covers the payment today. It asks whether the rent would still cover the payment under stress. It applies an assumed interest rate that is higher than the one you will actually pay, calculates the payment at that assumed rate, and then requires the rent to exceed it by a margin. That margin is the interest cover ratio, or ICR.

Two things follow, and both of them catch people out.

• The length of the fix changes the answer. Longer fixed terms are commonly assessed against a lower stress assumption than shorter ones, because the lender has more certainty about your payments. The same property and the same rent can support meaningfully different loan sizes depending on how long you fix for.
• Your own tax position changes the answer. Lenders commonly apply a higher required ICR to higher rate taxpayers than to basic rate taxpayers, because more of the rent will be lost to tax. Two landlords buying identical flats side by side can be offered different amounts.

For context, and this figure needs its date attached: the market average interest cover ratio on new buy to let lending reached 221% in the first quarter of 2026, up from 204% a year earlier, according to UK Finance. That rise happened because funding costs were falling through that period, not because lenders relaxed. It describes a quarter that has ended, and it is not a measure of the headroom available today.

Which brings us to the thing that has changed since the summer. Bank Rate has not moved since December. The cost of fixed money has. Swap rates, which is what lenders actually fund fixed products from, have risen by roughly 20 basis points over the past month, and the ten year gilt stood at 5.35% on 25 September, its highest since June 2008. Several major lenders have repriced upward. Stress assumptions follow funding costs rather than Bank Rate, so the amount a lender will offer can tighten while the headline rate sits perfectly still.

Hiten comments:

“If you stress tested a deal in July and you are still working from that number, in needs to be tested against current mortgage rates. Whilst the Bank of England base rate hasn’t changed this year, mortgage interest rates have slowly increased impacting the debt service cover ration calculations.”

Deposit, loan to value and the costs people forget

Buy to let usually needs a larger deposit than residential. Most mainstream lending sits at or below 75% loan to value, so a deposit of a quarter of the purchase price is the working assumption, with better terms available as you put in more. Some lenders go higher, particularly for standard properties and strong applicants, but the stress test often becomes the binding constraint before the loan to value cap does.

Budget for these as well, because they are the ones that get missed:

• Arrangement fees, which on buy to let are frequently charged as a percentage of the loan rather than a flat amount. A percentage fee on a large loan is a large fee, and the headline product that looks cheapest often is not once the fee is included.
• Valuation fees, which scale with property value.
• Legal costs, higher if you are buying through a company.
• Stamp duty at the higher rates for additional dwellings, covered in section 8.
• The cost of getting the property lettable, which for older stock now needs thinking about alongside the energy efficiency rules in section 8.

One practical trap worth knowing. Most term lenders will lend against the lower of purchase price and valuation for the first six months of ownership. If you buy something under value and expect to refinance immediately against the higher figure, check the lender’s policy first. Several lenders will consider day one remortgages and will lend against an improved value where works are properly evidenced. Several will not. This is lender policy rather than regulation, and it varies.

Personal name or limited company

This is the structural decision it depends on facts we would need to see.

The reason it became a live question is Section 24 of the Finance (No. 2) Act 2015. Individual landlords can no longer deduct finance costs, including mortgage interest, from rental income as a business expense. Instead they receive a tax credit worth 20% of those costs. For a basic rate taxpayer the effect is broadly neutral. For a higher or additional rate taxpayer it is not, because tax is calculated on rental income before finance costs are relieved, which can push people into higher bands on income they never actually received.

Companies are taxed differently. A company pays corporation tax on its profits after deducting finance costs in the normal way. That is why incorporation became attractive to higher rate taxpaying landlords with borrowing.

But it is not free, and the comparisons that circulate online tend to stop at the point where the company looks good:

• Getting money out of the company is a second taxable event. Corporation tax on profits, then income tax on dividends or salary when you extract them. A company is efficient for retaining and reinvesting profit, and less so if you need the income to live on.
• Moving existing personally held property into a company is normally a disposal for capital gains tax and a purchase for stamp duty. The tax can be substantial. We would advise that you speak with your accountant to discuss the tax impact.
• Company lending is a smaller market, and lenders commonly want personal guarantees from the directors.
• There are running costs. Accounts, filings, and an accountant who understands property.

General information only and not tax advice. The right answer depends on your marginal rate, whether you need the income now, how long you intend to hold, and what you already own. Get it modelled by an accountant before you buy anything, because it is far cheaper to decide this before the first purchase than to unpick it afterwards.

Hiten adds:

“The limited company question is the one where I see the most expensive mistakes, in both directions. People incorporate because someone at a networking event told them to, and people stay personal because incorporating sounds complicated. The decision to incorporate or keep in personal names depends entirely on individual circumstances and the ultimately investment objective.”

Portfolio landlords and the four property line

Once you have four or more mortgaged buy to let properties, lenders treat you differently. This comes from the Prudential Regulation Authority’s supervisory expectations, set out in SS13/16, which is a supervisory standard rather than a legal definition of what a landlord is.

In practice, crossing that line means a lender will normally want to look at the whole portfolio rather than just the property in front of it. Expect to be asked for:

• A schedule of every property, with values, rents and outstanding borrowing.
• A cashflow model for the portfolio as a whole.
• A business plan, and a sensible answer to what happens if rates rise or a property sits empty.
• Background portfolio testing, where the lender applies its own stress assumptions across everything you own, not only the new purchase.

The practical consequence is that a single weak property can block a good purchase. If you are approaching four, get the portfolio schedule in order before you need it, because assembling it under time pressure during a purchase is how deadlines get missed.

What lenders look for: criteria in practice

Criteria vary more in buy to let than in any other part of the mortgage market, which is most of the reason a broker earns their keep here. The common gates are these.

Minimum income

Many lenders set a minimum personal income, often around £25,000, for UK resident applicants. A meaningful number of lenders have no minimum income at all provided the rental calculation works, which matters for landlords whose income is mostly from property already.

First time landlords

Some lenders will not lend to a first time landlord at all. Others will, but restrict the property type or require you to be an existing homeowner. It is a solvable problem, but it narrows the field, so it is worth knowing before you fall in love with a property.

Living overseas

Expatriate buy to let is a specialist market with its own lenders. Minimum income requirements are commonly much higher than the UK resident figure, frequently £50,000 or equivalent, and the list of acceptable countries and currencies varies by lender. Rules here have moved recently, so check current positions rather than relying on what was true a year ago.

Age

Maximum age at the end of the term is a real constraint and it varies enormously. Some lenders cap at 75, some at 85, and a growing number have no upper limit for interest only buy to let where the exit is a sale. For older landlords this is frequently the single criterion that decides the lender.

The property itself

Flats above commercial premises, ex local authority, high rise, non standard construction, HMOs and multi unit freehold blocks all narrow the lender list, sometimes dramatically. Short leases do the same. None of these are dealbreakers in a specialist market, but each one changes who will lend and on what terms.

Interest only, fixes and product transfers

Around 91% of outstanding mortgage balances were on fixed rates in the first quarter of 2026, according to FCA data, so for most landlords the practical question is not whether to fix but for how long, and what happens at the end.

Three things are worth knowing well before your current deal ends.

• Product transfer windows commonly run three to four months before expiry, and several lenders have cut theirs from six. That is the window in which you can secure a new deal with your existing lender without a full application.
• A full remortgage offer is commonly valid for six months. So the work can be done early and the decision taken late, which is usually the right way round when nobody knows which way rates are going.
• Standard variable rates are discretionary. A lender sets its SVR and can change it when it chooses. It does not automatically follow Bank Rate, which a tracker does contractually. Rolling onto SVR because you ran out of time is the most expensive avoidable outcome in this whole guide.

UK Finance forecast, back in December 2025, that around 1.8 million fixed rate deals would end during 2026. That is a forecast rather than a live count, but it gives a sense of how many households and landlords are making this decision in the same window.

The compliance calendar most guides leave out

This is the section we could not find anywhere else, and it is now the part that changes landlord decisions most often. Four separate regimes are moving at once, and they interact with your borrowing in ways that are easy to miss until they are urgent.

The Renters’ Rights Act: the tenancy system has already changed

The Renters’ Rights Act 2025 received royal assent on 27 October 2025, and the main tenancy reforms commenced on 1 May 2026. The last date to serve a Section 21 notice was 30 April 2026.

• Section 21, the so called no fault eviction, is abolished. Possession now requires a ground under Section 8.
• Fixed term assured tenancies are gone. All tenancies became periodic.
• Rent can be increased once a year, by a Section 13 notice, and the tenant can challenge it at tribunal.
• Bidding wars are banned. You must advertise a rent and you cannot accept more than it.

Still to come: a Private Rented Sector Landlord Ombudsman, expected in 2028, and the Decent Homes Standard, scheduled for 2035. Awaab’s Law is expected to extend to the private sector, with timing not yet confirmed.

The PRS Database: registration is coming, regionally

A national database of private landlords and rented properties is being introduced under the same Act. Current expectation is a regional rollout beginning around December 2026, with full registration required by around mid November 2027. Landlords will receive a registration number, properties will have their own entry, and those details will need to appear in lettings adverts. Penalties for non compliance run to £7,000, rising to £40,000 for providing false information or for a continuing breach.

Timings and fees here are still moving. Treat the dates above as the current expectation rather than settled law, and check before you rely on them.

Making Tax Digital for Income Tax: already live for larger landlords

MTD for Income Tax began in April 2026 for landlords and sole traders with gross income above £50,000. The threshold falls to £30,000 in April 2027 and £20,000 in April 2028. Note that this is gross property income, before expenses and before mortgage interest, so more landlords are inside it than expect to be.

In scope means keeping digital records and filing quarterly updates, with deadlines of 7 August, 7 November, 7 February and 7 May, followed by a final declaration. Missed deadlines accrue points, and four points brings a £200 penalty.

EPC C: proposed for 2030, and worth planning for now

The government has proposed that privately rented homes in England and Wales meet a standard equivalent to EPC C by 1 October 2030. Four points matter here, and the first is the one most often skipped.

• It is not law yet. The primary powers and the statutory instrument are expected, with the SI not anticipated until 2027. Always treat this as proposed and subject to legislation.
• There is a proposed cost cap of £10,000 per property, or 10% of value for properties below £100,000. The government’s impact assessment put average expected spend at around £5,400.
• The assessment methodology is changing, to a metric combining fabric performance with either heating system or smart readiness. A property rated C under today’s certificate may not qualify under the reformed one.
• Energy efficiency is starting to affect lending. A small number of lenders price differently for better rated stock. It is not a market wide rule, and the differences are modest, but the direction is one way.

The reason to plan now rather than in 2029 is sequencing. Improvement works and a remortgage compete for the same money at the same time, and doing them in the right order is usually worth more than doing either one well.

Stamp duty: 5%, not 3%

The higher rates of stamp duty land tax for additional dwellings have been 5% since 31 October 2024, on top of the standard rates. You will still see 3% quoted in articles that were never updated. Companies purchasing residential property face a flat higher rate at the top end, and the 36 month window for reclaiming the surcharge where you are replacing a main residence continues to apply. Scotland and Wales operate their own systems with different rates and rules.

General information only and not tax advice.

Hiten comments:

“The compliance calendar is getting busier and busier leaving many landlords asking searching questions about whether it is all worth it. This is particularly the case since the introduction of the Renters Reform Act earlier this year. A quarter of a percent on a mortgage is a number you can plan around. Finding out in 2029 that four properties need work you have not budgeted for is harder.”

What the market looks like as we publish

Every figure here is dated, because in this market a number without a date is not information.

Lending volume	58,272 new buy to let loans worth £10.8bn in Q1 2026, up 3.26% by number and 7.02% by value year on year. UK Finance, published 15 July 2026
Gross rental yield	7.21% in Q1 2026, up from 6.93%. UK Finance. This is a gross yield, before costs, borrowing and tax
Interest cover ratio	Market average 221% in Q1 2026, up from 204%. UK Finance. A rear view figure from a falling rate quarter
Arrears	8,960 buy to let mortgages in arrears of more than 2.5% of balance in Q1 2026, with 810 possessions in the quarter. UK Finance
Rents	Average UK private rent £1,400 in August 2026, up 3.8% on the year. ONS, 16 September 2026
House prices	Average UK house price £273,000 in July 2026, up 1.4% on the year. ONS, 16 September 2026
Inflation	CPI 3.1% in the year to August 2026, a five month high. ONS, 16 September 2026
Bank Rate	3.75%, held on 17 September 2026 on a six to three vote, with three members voting for a rise to 4%. Bank of England
Funding costs	Two year swap 4.26% and five year 4.36%, both up around 20 basis points on the month. Ten year gilt 5.35% on 25 September 2026, the highest since June 2008

The story in those numbers is worth spelling out. Rent growth of 3.8% is running well ahead of house price growth of 1.4%, and ahead of inflation. The income case for holding property is strengthening at the same time as the capital case weakens. That points different landlords in different directions depending on why they own the property, and it is a better starting point for a decision than sentiment is.

Five mistakes we see most often

• Making an offer before testing the borrowing. The stress test, not the asking price, decides what is affordable. Find out first.
• Choosing a product on the headline rate alone. A percentage based arrangement fee on a large loan changes the ranking completely.
• Deciding the company question from a blog post. Including this one. It is arithmetic specific to you, and it needs an accountant.
• Leaving the remortgage until the deal has ended. The window opens months before expiry and standard variable rates are discretionary.
• Treating compliance as a later problem. Energy efficiency works, database registration and quarterly filing all have lead times, and they collide with each other.

Frequently asked questions

How much deposit do I need for a buy to let mortgage?

Usually at least 25% of the purchase price, because most mainstream buy to let lending sits at or below 75% loan to value. In practice the rental stress test frequently limits the loan before the loan to value cap does, so the deposit you need can be larger than the headline suggests.

How do lenders decide how much I can borrow on a buy to let?

They apply an assumed interest rate higher than the one you will pay, work out the payment at that rate, and require the rent to exceed it by a set margin known as the interest cover ratio. The length of your fixed term and your income tax position both change the required margin, so the same property can support different loan sizes for different borrowers.

Can I get a buy to let mortgage as a first time landlord?

Yes, though the lender list is narrower. Some lenders decline first time landlords outright, and others require you to already own your own home or restrict the property type. It is a solvable problem with the right lender.

Should I buy through a limited company?

It depends on your marginal tax rate, whether you need the rental income to live on, how long you intend to hold, and what you already own. Companies deduct finance costs in full where individuals get only a 20% tax credit, but extracting profit is taxed again and moving existing property into a company normally triggers capital gains tax and stamp duty. This is general information only and not tax advice, and it should be modelled by an accountant before you buy.

What is a portfolio landlord?

Broadly, a landlord with four or more mortgaged buy to let properties. It comes from the Prudential Regulation Authority’s supervisory expectations in SS13/16 rather than from statute. Once you cross that line lenders will assess your whole portfolio, not just the property you are buying.

Has Section 21 really been abolished?

Yes. Section 21 no fault evictions ended on 1 May 2026 under the Renters’ Rights Act 2025, and the last date to serve a notice was 30 April 2026. All assured tenancies are now periodic, and possession requires a ground under Section 8.

Do I have to register on the PRS Database?

Yes, once it reaches your region. A regional rollout is expected to begin around December 2026 with full registration required by around mid November 2027. Your registration number will need to appear in lettings adverts, and penalties for non compliance reach £7,000, or £40,000 for false information or a continuing breach. Timings are still moving, so check the current position.

Does my rental property need to be EPC C by 2030?

That is the proposal for England and Wales, with a date of 1 October 2030, but it is not yet law and the statutory instrument is not expected until 2027. There is a proposed cost cap of £10,000 per property and the assessment method is also changing, so a property rated C today may not qualify under the reformed metric. Plan for it, and describe it as proposed.

Is buy to let still worth it in 2026?

That depends entirely on why you own the property. Rents rose 3.8% in the year to August 2026 while house prices rose 1.4%, so the income case is strengthening while the capital case weakens. Compliance costs and tax treatment have both moved against leveraged higher rate taxpayers. It is an arithmetic question, and the arithmetic is specific to you.

Where to go next

If you are buying, refinancing, or simply trying to work out whether your portfolio still does what you set it up to do, the useful next step is a conversation with someone who can see the whole picture at once: the borrowing, the structure and the compliance calendar together, rather than one at a time.

Hiten concludes:

“Send us the numbers and we will tell you where you actually stand today, not where you stood in July. That is a twenty minute conversation and it costs nothing, and it is a great deal cheaper than finding out after you have exchanged.”

Visionary Finance is a whole of market mortgage broker based in Milton Keynes, working with landlords and property investors across the UK.

Call 01908 465 100 or email [email protected] to talk it through.

Important information

This guide is general information and is not advice. It does not take account of your circumstances and should not be relied on as a recommendation. Tax content is general information only and not tax advice, and tax treatment depends on individual circumstances and may change. You should take advice from a qualified accountant or solicitor on tax and legal matters.

The Financial Conduct Authority does not regulate most buy to let mortgages. Your property may be repossessed if you do not keep up repayments on your mortgage.

All figures are attributed and dated at the point of publication on 8 October 2026. Market data moves, and figures quoted here will age. Sources: UK Finance, Office for National Statistics, Bank of England, Financial Conduct Authority, Ministry of Housing, Communities and Local Government, HM Revenue and Customs, Moneyfactscompare, Trading Economics.

Visionary Finance Ltd is authorised and regulated by the Financial Conduct Authority. Registered in England and Wales number 06475028. Registered office: Ground Floor, 5 Whittle Court, Knowlhill, Milton Keynes, MK5 8FT.