RealYield LogoRealYield

Section 24 Tax Calculator for UK Landlords

See exactly how Section 24 affects your rental income. Compare your tax bill across different income bands and understand the true cost of mortgage interest restrictions.

Your Property Details
Enter your annual figures to see the Section 24 impact
£

Service charges, repairs, agent fees, etc.

£

Interest-only payment × 12

£

Want to see full cashflow analysis including stress testing and scenario comparison?

Your Section 24 Tax Impact
Gross Rental Income£12,000
Operating Costs-£2,000
Mortgage Interest-£5,000
Net Income (Pre-Tax)£5,000

Section 24 Tax Calculation

Taxable Profit (Interest NOT deductible)£10,000
Gross Tax @ 40%£4,000
Section 24 Relief (20% credit)-£1,000
Tax Bill£3,000

Cashflow After Tax

What actually hits your bank account

£2,000

Section 24 Impact

You're paying £1,000 more in tax per year compared to pre-2017 rules when mortgage interest was fully deductible.

Compare Across Tax Bands

Basic (20%)

£1,000

+£0 burden

Higher (40%)

£3,000

+£1,000 burden

Additional (45%)

£3,500

+£1,250 burden

Frequently Asked Questions

Related Tools

Personal vs Ltd Company Calculator

Compare tax efficiency between personal ownership and a limited company structure.

RealYield Calculator

Full property analysis with stress testing, scenario comparison, and AI insights.

Ready for a complete property analysis?

RealYield goes beyond tax calculations — see your true net yield, monthly cashflow, and stress test your portfolio against rate rises.

Guides behind these numbers

Plain-English reading on the rules and strategy behind this calculator.

All insights
26 June 2026Tax

Section 24: The Tax Rule That Is Costing Landlords Thousands

Section 24 prevents individual landlords from deducting mortgage interest as an expense. Instead, you get a 20% tax credit. For higher-rate taxpayers, the maths can push your effective tax rate on real profit to 100%. Here is how it works, with worked examples.

29 May 2026Tax

Landlord Self-Assessment: A Step-by-Step Walkthrough for the 2025-26 Tax Return

The 2025-26 tax return is due online by 31 January 2027. For landlords, the key is getting rental income, allowable expenses, and Section 24 mortgage interest right. This is the complete walkthrough, with a worked example showing what Section 24 costs a higher-rate taxpayer.

March 5, 2026Tax

Tax Relief on Mortgage Interest: What UK Landlords Can Still Claim in 2026

Mortgage interest relief has changed dramatically for landlords. Here is exactly how the 20% tax credit works, who it helps, and the strategies to maximise your position.