Buy-to-Let Mortgages Explained: A 2026 Guide for UK Landlords

If you’re weighing up whether to become a landlord, a buy-to-let mortgage is almost certainly the first hurdle you’ll need to clear. Search interest in “buy to let mortgage” has stayed the highest of any mortgage type on Google this year, and it’s easy to see why — with rental demand still outstripping supply in many parts of the UK, property remains an attractive way to build long-term income and capital growth.

But buy-to-let mortgages work very differently from the residential mortgage you’d use to buy your own home. Lenders assess them differently, price them differently, and expect a bigger deposit. This guide walks through exactly how buy-to-let mortgages work in 2026, what you’ll need to qualify, and how to find the most competitive rate for your circumstances.

What is a buy-to-let mortgage?

A buy-to-let (BTL) mortgage is a loan specifically for purchasing a property you intend to rent out rather than live in. Instead of being assessed mainly on your personal income, most lenders base affordability on the rent the property is expected to generate.

Buy-to-let mortgages are available on:

• Standard buy-to-let – a single self-contained property let to one household or tenancy.
• HMO (House in Multiple Occupation) – a property let room-by-room to three or more unrelated tenants who share facilities.
• Multi-unit freehold blocks (MUFBs) – several self-contained flats within one freehold title.
• Holiday let mortgages – a separate product category for short-term/holiday lets, priced and assessed differently again.

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

Most lenders ask for a minimum deposit of 25% of the property’s value, though some will consider 20% for strong applicants, and rates improve noticeably once you reach 60% loan-to-value (LTV) or lower. The bigger the deposit, the wider your choice of lenders and the sharper the rate you’ll be offered.

How buy-to-let affordability is worked out: the rental stress test

Rather than multiplying your salary, lenders apply a rental “stress test” to make sure the expected rent comfortably covers the mortgage payment. This is usually expressed as an Interest Cover Ratio (ICR):

• Individual landlords (basic-rate taxpayers): typically 125% of the mortgage payment at a notional stress rate.
• Higher-rate taxpayers and limited company applicants: typically 145%, reflecting the different tax treatment.
• Stress rate: lenders test affordability against a rate higher than your actual pay rate (often 5.5%–7%, depending on whether you’re taking a short or long-term fixed deal), to ensure the numbers still work if rates rise or the property sits empty for a period.

In practice, this means the rental income needs to be significantly higher than the monthly mortgage payment — often by a wide margin — before a lender will approve the loan. A broker can run these numbers for you against a real panel of lenders before you make an offer on a property, which avoids the disappointment of a mortgage falling through after an offer has been accepted on a property you intend to purchase.

Personal name vs limited company: which is better?

An increasing number of landlords — particularly those with more than one property, or who are higher-rate taxpayers — buy through a limited company (an “SPV,” or Special Purpose Vehicle) rather than in their own name. This is because mortgage interest relief for individual landlords has been restricted, while limited companies can still offset finance costs against rental profits before calculating corporation tax.

There’s no single right answer here. It depends on your income tax band, whether you plan to grow a portfolio, your long-term exit plans (personal Capital Gains Tax vs corporation tax and dividend tax on withdrawal), and your appetite for the slightly higher rates typically charged on limited company BTL products. This is genuinely one of the areas where paying for proper advice — from both a mortgage broker and an accountant — pays for itself many times over.

Buy-to-let mortgage rates in 2026

Buy-to-let rates broadly track the same market forces as residential mortgages — the Bank of England Bank Rate, swap rates, and lender competition — but typically sit slightly above equivalent residential deals to reflect the higher risk lenders attach to rental property. Rates and criteria change frequently, so rather than quote a number that may be out of date by the time you read this, the most reliable way to see what’s currently available is to compare live buy-to-let deals with a whole-of-market broker who can search the full lender panel for your deposit size and tax status, not just the handful of lenders on the high street.

Fixed, tracker or discount for a rental property?

Many landlords prefer the payment certainty of a fixed rate, particularly if they’re running tight margins on rental yield. Others opt for a tracker or discount deal, betting that variable rates will fall or wanting the flexibility to remortgage without early repayment charges. The right choice depends on your risk tolerance, how long you plan to hold the property, and your wider portfolio strategy — something worth talking through with an adviser rather than guessing.

Get whole-of-market buy-to-let advice

Buy-to-let lending criteria vary hugely from one lender to the next, and getting it wrong can mean a wasted valuation fee or a collapsed purchase. As a whole-of-market broker with access to 109+ lenders, Moorfield Mortgages compares buy-to-let deals across the market — including specialist lenders for HMOs, limited companies and portfolio landlords — to find the right fit for your circumstances.

[Book your free, no-obligation buy-to-let mortgage consultation with Moorfield Mortgages today.]

This article is for general information and does not constitute financial advice. Mortgage and rental criteria are correct at the time of writing and subject to change. Your property may be repossessed if you do not keep up repayments on your mortgage.