Landlord tax calculator with Section 24
See your taxable rental profit, the tax after the 20% finance-cost reduction, and how much more you pay than under the rules before 2017.
Your result shows here. It updates as you type.
This does not send anything to HMRC. You type the totals into HMRC-recognised software or a bridging tool.
Figures are estimates for planning. They are not tax advice.
Rates checked on gov.uk on 6 November 2026.
Keep your rental records in a spreadsheet
The Landlord MTD Record Book is in the shop now, £12 as a one-off download. It splits finance costs out for Section 24, handles joint ownership and shows the totals for each quarterly update. Read what changes for landlords from April 2027, and what you can claim.
Get the record book, £12Questions people ask
What is Section 24?
Since 6 April 2020, landlords of residential property cannot deduct mortgage interest from their rent before working out tax. Instead you take a tax reduction of 20% of your finance costs.
Who does it cost money?
Mostly higher-rate taxpayers, and basic-rate taxpayers whose rental profit pushes them into the higher rate. If you pay basic rate either way, the 20% reduction matches the 20% tax you would have saved, and the cost is nil.
How do joint owners work it out?
Each owner takes their own share of the rent, costs and interest, and is taxed on that share with their own other income. Type your ownership share and use the full property figures.
Can I use the £1,000 property allowance as well?
Not if you claim the finance cost reduction on residential property. You also cannot use it with Rent a Room. If you take the allowance, you cannot deduct actual expenses.
Free: the one-page MTD checklist
Every quarterly date, what to do before each update, and what happens if you miss one. Join the list and we email you a short reminder a week before each deadline. Unsubscribe any time.
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