Section 24 Tax Calculator
See how much extra income tax the Section 24 mortgage-interest restriction costs you, based on your rental income, mortgage interest and tax band.
Section 24 Tax Calculator
Calculate how much extra tax you're paying due to Section 24 mortgage interest restriction.
This calculator shows the extra tax you pay under Section 24 compared to the old system where full mortgage interest was deductible.
How Section 24 works
Section 24 of the Finance (No. 2) Act 2015 removed higher-rate relief on residential mortgage interest for individual landlords. Since April 2020 you can no longer deduct mortgage interest as an expense. Instead, your full rental income is taxed at your marginal rate and you receive a basic-rate (20%) tax credit on the finance costs.
For a basic-rate taxpayer the 20% credit matches the 20% rate, so there is little or no extra cost. For higher-rate (40%) and additional-rate (45%) landlords the credit stays at 20% while the income is taxed at 40% or 45%, leaving a wedge of 20 or 25 percentage points on the mortgage interest. That wedge is the extra tax this calculator estimates.
Section 24 applies to individuals (including joint owners), not to companies. A limited company deducts mortgage interest in full against its profits, which is one of the main reasons landlords weigh up incorporation.
From 2027/28, property income in England, Wales and Northern Ireland will be taxed at 22%, 42% and 47%, and the Section 24 credit rises to the new 22% basic rate. Basic-rate landlords still see the credit match the rate (no new wedge); higher and additional-rate landlords get a small improvement (20% to 22%), but the finance-cost wedge remains. This calculator uses current 2026/27 rates.
Paying more tax because of Section 24?
There are legitimate ways to reduce the impact, from how the property is owned to whether incorporation makes sense for your portfolio. Tell us about your situation for a no-obligation review.