Section 24 Buy-to-Let Tax Details
📊 Section 24 Income & Tax Breakdown
Introduced in Section 24 of the Finance (No. 2) Act 2015, Section 24 fundamentally changed how individual UK buy-to-let landlords are taxed on residential property rental income.
Prior to Section 24, landlords could deduct 100% of mortgage interest from rental income before calculating tax. Under Section 24, landlords are taxed on 100% of gross rental income, receiving only a 20% basic rate tax credit for mortgage interest.
⚙️ Statutory Section 24 Rules & Math for 2026/27
1. The Gross Rental Tax Trap
- No Direct Expense Deduction: Mortgage interest and finance costs are NO LONGER allowable business deductions against rental income for individual taxpayers.
- Inflated Adjusted Income: Adding gross rental income directly to your employment salary can push basic rate (20%) taxpayers into the 40% higher rate tax bracket, triggering higher tax rates across all personal income.
2. The 20% Basic Rate Tax Credit Formula
- Tax Credit: Calculated as 20% of your annual mortgage interest expense (or 20% of net property profits, whichever is lower).
- Higher Rate Penalty: Higher rate (40%) and additional rate (45%) landlords suffer a 20% to 25% tax shortfall on their mortgage interest outlays.
3. Limited Company (SPV) Exemption
Section 24 applies ONLY to individual landlords. Buy-to-let properties held inside a Limited Company (SPV) can still deduct 100% of mortgage interest as a full business expense against 19% to 25% Corporation Tax.
📊 Practical Section 24 Worked Examples
Below are two worked calculation examples illustrating Section 24 tax impacts:
- Gross Rental Income: **£24,000.00**
- Mortgage Interest Expense: **£10,000.00**
- Tax on Gross Rent (40% Higher Rate): £24,000 × 40% = **£9,600.00**
- Section 24 Tax Credit (20% of £10k interest): **-£2,000.00**
Calculation: Net rental tax payable = £9,600 - £2,000 = £7,600.00. Net cash profit remaining = £24k - £10k interest - £7.6k tax = £6,400.00.
- Gross Rental Income: **£30,000.00**
- Mortgage Interest Expense: **£20,000.00**
- Tax on Gross Rent (40% Higher Rate): £30,000 × 40% = **£12,000.00**
- Section 24 Tax Credit (20% of £20k interest): **-£4,000.00**
Calculation: Net tax = £8,000.00. Net cash remaining = £30k rent - £20k interest - £8k tax = £2,000.00 profit.
📑 Common Pitfalls & Landlord Tax Warnings
- Child Benefit & Personal Allowance Claws: Because Section 24 inflates your gross taxable income by adding gross rent to salary, it can push landlords past the £60,000 High Income Child Benefit Charge (HICBC) threshold or the £100,000 Personal Allowance taper threshold.
- Transferring Property to a Ltd Company Incurs Stamp Duty (SDLT) and CGT: Existing landlords cannot simply transfer property into a Limited Company tax-free. Transferring incurs Stamp Duty Land Tax (SDLT) at higher residential rates plus Capital Gains Tax (CGT) on market value appreciation.
- Allowable Repair Expenses Are Still Deductible: While mortgage interest is restricted, genuine property maintenance, repairs, letting agent fees, landlord insurance, and safety certificate costs remain 100% tax-deductible expenses.
❓ Frequently Asked Questions (FAQ)
For higher-rate taxpayers or investors planning to build a property portfolio, buying new properties through a Limited Company (SPV) is usually far more tax-efficient because 100% of mortgage interest remains deductible against Corporation Tax.
An SPV is a limited company set up specifically to buy, hold, and let residential real estate (typically registered under SIC code 68209). Specialized buy-to-let mortgage lenders offer dedicated SPV mortgage products.
Yes! Adding gross rental income (without deducting mortgage interest) can push a basic rate taxpayer's total taxable income over the £50,270 higher rate threshold, subjecting part of their income to 40% tax.
Enter your total gross annual rental income and allowable repair expenses in the UK Property pages (SA105). Enter your total annual mortgage interest paid in **Box 44 ('Residential finance costs')**. HMRC automatically calculates the 20% tax credit.