Calculator
Limited company mortgage calculator: company vs personal-name tax, on your numbers
Section 24 changed the arithmetic for higher-rate landlords, but it did not make the company answer automatic. Enter your rent, mortgage interest and tax band below and the model runs both structures side by side over five or ten years: personal ownership under the restricted 20% interest credit, against an SPV paying corporation tax, with dividends extracted or profits retained.
What the limited company tax calculator compares
The model takes one rental property, or one portfolio's totals, and taxes the same cash twice, once under each structure. In your own name, rental profit is added to your other income and taxed at your marginal rate, with mortgage interest relieved only through Section 24's 20% basic-rate credit. Inside a limited company, the interest is a fully deductible business expense, the remaining profit pays corporation tax at 19 to 25% depending on the band, and you then choose what happens next: extract everything as dividends, taxed above the £500 allowance at your dividend rate, or retain the profit inside the SPV for the next deposit. The difference line at the bottom is the cumulative cash gap between the two structures over your chosen horizon.
When the SPV wins, and when it does not
Three inputs drive almost every result. Your marginal tax band: at 40% or 45%, Section 24 bites and the company usually pulls ahead; at 20%, the personal credit broadly offsets the interest and the gap narrows or reverses. Your gearing: the more mortgage interest in the model, the harder Section 24 punishes personal ownership, so a heavily leveraged purchase favours the company far more than an unencumbered one. And your extraction plan: a landlord who retains profits to compound into further purchases keeps the full corporation tax advantage, while one who extracts every pound as dividends hands part of it back. What the calculator deliberately does not capture is the cost side of the company, the stamp duty surcharge on the purchase, accountancy, and company mortgage pricing that typically runs 0.20 to 0.40% above the personal-name equivalent, which is why a marginal on-screen win deserves a proper conversation before you incorporate.
The full mechanics are in our limited company buy-to-let tax guide, and the product side, deposits, the 125% ICR, lender appetite, lives on the limited company buy-to-let mortgages hub.
From comparison to mortgage
If the company side wins on your figures, the next questions are practical: setting up the SPV with the right SIC codes, routing the deposit in as a documented director's loan, and choosing from the lenders who underwrite company cases daily, several of whom are intermediary-only and never quote the public. We arrange limited company buy-to-let across a 100+ lender panel, the initial consultation is fee-free, and we will happily tell you if your numbers say stay personal.
Limited company tax calculator FAQs
Is it more tax efficient to buy a buy-to-let through a limited company?
For higher-rate and additional-rate taxpayers with meaningful mortgage debt, usually yes: inside the company, the interest is fully deductible and profits face corporation tax at 19 to 25%, where personally you pay income tax on profits with only a 20% credit for the interest under Section 24. For basic-rate taxpayers, or landlords with little borrowing, the company's extra costs and dividend tax on extraction often cancel the advantage. The calculator shows which side of that line your numbers fall.
How does Section 24 change the personal-name calculation?
Since 2020, mortgage interest is no longer deductible from personal rental profits. You pay income tax at your marginal rate on the gross rental profit before interest, then receive a tax credit worth 20% of the interest paid. A higher-rate taxpayer therefore pays 40% on income that the mortgage has already consumed, which is why heavily geared personal-name portfolios can produce tax bills larger than their actual cash profit.
What corporation tax rate does the model use?
The current bands: 19% small profits rate up to £50,000, 25% main rate from £250,000, with marginal relief tapering between the two. The auto setting applies the band your modelled profit lands in; you can force 19% or 25% if your company has other income or associated companies that change the band.
Does the calculator account for dividend tax when I take the money out?
Yes, that is the extract-all option: post-corporation-tax profit is paid out as dividends, taxed at 8.75%, 33.75% or 39.35% by your marginal band after the £500 dividend allowance. The retain option models leaving profits inside the SPV to recycle into the next deposit, which is where the company structure compounds hardest, no dividend tax falls due until you actually extract.
What does the model leave out?
Stamp duty including the company surcharge, accountancy costs, the slightly higher company mortgage rate, capital gains treatment on exit and inheritance planning all sit outside this model, and any of them can move a marginal case. It is a structure comparison, not advice. We model the full picture, alongside your accountant where useful, on a fee-free initial call.
Can I switch an existing personal property into the company?
Yes, but it is a sale at market value, not a paperwork change: capital gains tax on your disposal, stamp duty with the surcharge on the company's purchase, and a full remortgage in the company name. The transfer maths is different from the new-purchase maths this calculator runs, see our transfer guide before deciding.