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Section 24 Mortgage Interest Relief Worksheet 2026/27
See exactly how Section 24 restricts your mortgage interest relief to a 20% tax credit, and what it means for your actual tax bill.
What’s Included
- Editable input cells for rental income, expenses, mortgage interest and your other income.
- Automatic calculation of your taxable property profit under Section 24 rules and your 20% mortgage interest tax credit.
- Plain-English explanation of why this differs from how mortgage interest relief used to work before April 2020.
Why This Matters
Since Section 24 was fully phased in, landlords can no longer deduct mortgage interest from their rental income before working out tax — instead, the full rental profit is taxed, and a 20% tax credit is applied afterwards. This catches many landlords off guard, particularly higher-rate taxpayers who used to get 40%+ relief and now only get 20%, and landlords who find they've been pushed into a higher tax band because their gross rental profit (not profit after interest) counts towards their total income.
Frequently Asked Questions
No. Section 24 only applies to individual landlords who own property personally. Landlords who hold property through a limited company can still deduct mortgage interest as a normal business expense, which is one reason some landlords have incorporated.
This is the core effect of Section 24 — the relief is fixed at the basic rate (20%) regardless of what rate you actually pay tax at, so higher and additional rate taxpayers get proportionally less benefit than they did under the old rules.
Yes, potentially. Because your full rental profit (before mortgage interest is deducted) counts towards your total taxable income, some landlords find their total income crosses into a higher tax band even though their actual cash profit, after paying the mortgage, is lower.
Sources
- Section 24 rules from GOV.UK — Changes to tax relief for residential landlords (checked 2026)