Section 24 Tax Impact Calculator

Section 24 restricted mortgage interest tax relief to a 20% basic-rate credit from April 2020. For higher-rate and additional-rate landlords, that means your taxable rental profit is now calculated as if you had no mortgage — and then you get a small credit back. On a leveraged portfolio, the difference between "before Section 24" and "after Section 24" can be thousands of pounds a year.

This calculator shows you the exact cost of Section 24 for your circumstances: your gross rental income, your allowable expenses, your mortgage interest, and your marginal tax band. It outputs your tax bill pre-Section 24 (the old rules) and post-Section 24 (the current rules), so you can see the gap in pounds.

Use it alongside the Incorporation Decision Calculator to see whether moving to a limited company structure pays back the SDLT and CGT cost of transfer.