Quick Answer: BTL Interest-Only in 2026
Around 80% of UK BTL mortgages are interest-only in 2026. You pay just the monthly interest, never reducing the capital balance — so at the end of the term, you owe the same amount you originally borrowed. Lower monthly payments (typically 30-40% less than repayment), better rental coverage at stress test, and improved cash flow are the main attractions. The trade-off: you build no equity through repayments (only through property appreciation) and need a credible strategy to repay the capital at term end — usually sale of the property, sale of other assets, or remortgaging onto a new IO product. All mainstream BTL lenders offer IO, including The Mortgage Works, BM Solutions, Accord, Coventry BS for Intermediaries, Paragon, Aldermore, Precise, and Kensington. Typical rate premium: zero — IO is the default BTL structure, not a specialist product.
Interest-only is so dominant in BTL because it makes the rental yield maths work. A £200,000 BTL at 5.3% interest-only is £883/month interest; the same loan on repayment over 25 years is £1,206/month. On £1,500/month rent, the IO version delivers £617/month gross profit; the repayment version delivers £294/month. Most landlords need that cash flow to make the investment viable after maintenance, voids, agent fees, and tax.
How Interest-Only Works on a BTL
With an interest-only mortgage, your monthly payment covers only the interest charged on the loan that month. The capital balance never reduces. At the end of the term — typically 25-30 years — you owe exactly the same amount you borrowed at the start.
Worked example. £200,000 BTL mortgage at 5.3% over 25 years:
| Component | Interest-only | Repayment |
|---|---|---|
| Monthly payment | £883 | £1,206 |
| Balance after 5 years | £200,000 | £177,750 |
| Balance after 10 years | £200,000 | £153,650 |
| Balance after 25 years (term end) | £200,000 (owed in full) | £0 (fully paid off) |
| Total interest paid over 25 years | £264,900 | £161,800 |
| Total monthly cost difference | - | £323/month more than IO |
Interest-only costs more total interest over 25 years (£264,900 vs £161,800) because the capital balance never reduces — so the interest charge on the full balance is paid every month, forever. Repayment is more efficient on total interest but requires higher monthly outflows that the rental yield may not support.
Why this matters for cash flow. On the same £1,500/month rent: IO leaves £617/month gross profit (before management costs and tax); repayment leaves £294/month. After 25% letting agent fees (£375/month), maintenance reserve (£100/month), and Section 24 tax impact, the IO version remains profitable; the repayment version is often loss-making month to month.
Why 80% of UK Landlords Choose Interest-Only
Four reasons interest-only dominates the BTL market in 2026:
1. Cash flow and rental yield. The lower monthly payment of interest-only allows the rental income to comfortably cover the mortgage plus expenses with margin. Landlords building portfolios prefer monthly cash flow to capital accumulation — they can reinvest cash flow into more properties rather than locking it into equity that's not easily accessible.
2. Rental coverage stress test efficiency. BTL lenders size the loan based on rental income covering the interest at a stressed rate — not the full repayment amount. So interest-only mortgages allow you to borrow more against the same rental income. A £1,500/month rent might support a £200,000 IO mortgage but only a £150,000 repayment mortgage at the same lender's stress test — a £50,000 difference in lending capacity.
3. Tax efficiency under Section 24. Since the Section 24 mortgage interest relief restriction (fully phased in by April 2020), only mortgage interest payments qualify for the 20% basic-rate tax credit. Capital repayments don't reduce your tax bill at all. So interest-only payments are tax-relievable; repayment payments are partly not. The IO structure maximises the tax-deductible portion of your monthly outflow.
4. Capital appreciation strategy. Most UK landlords expect property values to rise over the long term. They plan to repay the capital from eventual sale or from refinancing as the property's value grows. Interest-only keeps monthly costs low while letting capital appreciation accrue — the 'leverage' strategy. This works when prices rise; it's exposed when they fall.
Section 24 Tax Treatment of Interest-Only Payments
Section 24 of the Finance (No. 2) Act 2015 fundamentally changed how UK landlords are taxed on mortgage interest. As of 2026, here's the rule:
- For individual landlords: Mortgage interest is no longer deductible from rental income as a business expense. Instead, you receive a 20% basic-rate tax credit on the interest paid.
- For limited company landlords: The Section 24 restriction does NOT apply. Companies can fully deduct mortgage interest as a business expense before calculating Corporation Tax.
Practical impact on an interest-only BTL (individual landlord, higher-rate taxpayer):
| Item | Annual amount |
|---|---|
| Rental income | £18,000 |
| Mortgage interest (£200k IO at 5.3%) | £10,596 |
| Other deductible expenses (agent fees, maintenance) | £4,000 |
| Taxable rental profit (before interest) | £14,000 |
| Income tax at 40% | £5,600 |
| Less: 20% credit on mortgage interest (£10,596 × 20%) | -£2,119 |
| Net tax payable | £3,481 |
| After-tax cash flow (after mortgage interest) | -£77 |
This higher-rate landlord earns £18,000 rent, pays £10,596 in mortgage interest, £4,000 in other costs, and £3,481 in tax — netting negative £77/year in cash flow. Pre-Section 24 (when interest was fully deductible), the same landlord would have netted £2,000+ positive. This is why many higher-rate landlords have moved their portfolios into limited companies, where Section 24 doesn't apply.
Should this change your IO decision? Section 24 affects IO and repayment equally — both have the same mortgage interest cost in any given month, so the tax credit is identical. The decision between IO and repayment is about cash flow vs equity building, not tax efficiency. Where Section 24 matters more is the overall question of personal vs limited company ownership.
Capital Repayment Strategies: How You'll Repay at the End
The lender will want to know how you plan to repay the £200,000 (or whatever your balance is) at the end of the term. Acceptable strategies, in order of frequency:
1. Sale of the property (most common — ~70% of landlords). The plan is that the property's value at term end will exceed the mortgage balance. £200,000 borrowed today; if the property is worth £300,000+ in 25 years, the sale proceeds repay the mortgage with surplus equity left for you. Lenders accept this strategy without much scrutiny because rising property values are the assumption behind BTL investment. The risk: if values are flat or have fallen, you may struggle to repay from sale alone.
2. Sale of other investments / assets. Stocks & shares ISA portfolios, additional BTL properties not being sold, defined contribution pension lump sums (post-55), inheritance expectations. Lenders accept these as evidence if documented — investment platform statements, pension forecasts, life insurance death benefits.
3. Switching to repayment partway through the term. Some landlords plan to switch from IO to repayment after 10-15 years, once their portfolio is mature and the property has built equity. This means higher monthly payments later in life but full repayment by term end. Most lenders allow this switch via product transfer or remortgage.
4. Endowment policy or savings plan. Historic strategy — using a regular savings vehicle designed to mature to the mortgage balance. Largely fallen out of fashion in BTL since endowments were widely mis-sold in the 1990s and stopped performing reliably.
5. Remortgaging onto a new IO product. Effectively rolling the IO mortgage forward indefinitely. This is acceptable in the lender's assessment if you can demonstrate continued ability to remortgage at term end (age, income, property condition). However, you cannot guarantee that interest-only will still be available, that you'll meet criteria, or that rates will be acceptable. Most lenders will accept this as a backup strategy but want a primary plan (usually sale).
When Repayment Beats Interest-Only
Interest-only isn't always the right choice. Three scenarios where repayment makes more sense:
1. You bought the property to keep long-term and have strong cash flow surplus. If the rent comfortably covers a repayment payment with margin to spare, repayment builds equity automatically over 25 years. By the end, you own the property outright — a £200,000+ asset producing £18,000+/year rental income. Total wealth created is significantly higher than IO + sale.
2. You're approaching retirement. Owning the BTL property mortgage-free in retirement gives you a clean, low-risk income stream (rental yield) without the worry of repaying capital. Switching from IO to repayment in your 50s, with 10-15 years to clear the balance, can produce a debt-free property by retirement.
3. You expect property values to be flat or falling. The IO sale-strategy assumes capital appreciation. If you have a bearish view on UK property prices, repayment removes that risk — you're guaranteed to own the property free and clear regardless of value movements.
The hybrid approach. Some landlords use part-and-part mortgages: 50% interest-only, 50% repayment. This balances cash flow (IO portion) with equity building (repayment portion). Many specialist BTL lenders offer this structure, including Paragon, Aldermore, and Precise. Costs slightly more administratively but can be the right middle ground.
Common Pitfalls and Risks of BTL Interest-Only
Five risks specific to interest-only BTL that landlords often underestimate:
1. The capital repayment trap at term end. A surprising number of landlords reach term end without a viable repayment plan, particularly if they've inherited the mortgage or moved between lenders without re-examining the exit strategy. By then, options narrow — selling in a soft market, remortgaging at age 65+ with limited lender choice, or refinancing onto more expensive products. Plan the exit at year 15, not year 25.
2. Property value risk. If you're banking on sale at term end, a 10-15% market dip at the wrong time can wipe out the equity buffer. Run the maths with property values flat for 25 years (no growth) — if the IO sale strategy still works, good; if not, build a backup.
3. Section 24 cash flow squeeze for higher-rate landlords. As shown above, higher-rate individual landlords with significant interest costs can find their post-tax cash flow turning negative. Consider limited company ownership if expanding the portfolio.
4. Rising interest rates. When your 5-year fix ends, you remortgage at the prevailing rate. If rates have risen, your monthly interest payment rises directly — and Section 24 means the higher cost isn't fully tax-relievable. Build a 2-3% rate-rise buffer into your rental coverage planning.
5. Lender attitude shifts. Post-2014 MMR, many lenders have tightened interest-only criteria over time. New IO BTL applications now require evidence of the repayment strategy at application — and lenders increasingly scrutinise existing IO portfolios at remortgage. Some have stopped offering IO altogether or restricted it to high-LTV applications. Keep your portfolio documentation up to date.
Important: Your home may be repossessed if you do not keep up repayments on your mortgage. There will be a fee for mortgage advice. The actual rate available will depend on your circumstances. Think carefully before securing other debts against your home.