Buy-to-Let Calculator (UK)
UK BTL yield with the 3% SDLT surcharge, the 145% @ 5.5% ICR stress test and Section 24 mortgage-relief drag.
Formula
Three UK-specific drags stack: the 3% additional-property SDLT surcharge, the ICR stress test that caps leverage off rent (not value), and Section 24 restricting mortgage-interest relief to a 20% credit — pushing higher-rate taxpayers toward limited-company structures.
Not financial advice — for informational and analytical use only. Verify all figures with a qualified professional before acting on them.
Need buy-to-let calculator results fast? Analysts, founders, traders and finance professionals use the Buy-to-Let Calculator to skip the spreadsheet and get a defensible answer in one step — free, private and instant.
About Buy-to-Let Calculator (UK)
UK BTL yield with the 3% SDLT surcharge, the 145% @ 5.5% ICR stress test and Section 24 mortgage-relief drag. Three UK-specific drags stack: the 3% additional-property SDLT surcharge, the ICR stress test that caps leverage off rent (not value), and Section 24 restricting mortgage-interest relief to a 20% credit — pushing higher-rate taxpayers toward limited-company structures. The governing relationship is ICR = rent / stressed interest; must exceed 125–145%. The Buy-to-Let Calculator computes entirely in your browser — free, private (your figures never leave your device) and instant, recalculating live as you change any input.
How to use Buy-to-Let Calculator (UK)
- 1Enter Purchase price (currency), Monthly rent (currency), BTL mortgage (currency), Mortgage rate (IO) (%), Lender stress rate (%), ICR required (%) into the Buy-to-Let Calculator.
- 2The result is computed automatically using ICR = rent / stressed interest; must exceed 125–145% — there is no button to press.
- 3Change any input to model a different scenario, then copy or share the result.
Why use Buy-to-Let Calculator (UK)?
- ✓Computes buy-to-let calculator instantly with the correct formula — no spreadsheet needed
- ✓100% free and unlimited, with no sign-up, login or paywall
- ✓Runs entirely in your browser, so the figures you enter stay private
- ✓Shows the formula, a live worked example and references so you can defend the number
Frequently asked questions
What is the formula behind the Buy-to-Let Calculator?+
Buy-to-Let Calculator uses ICR = rent / stressed interest; must exceed 125–145%. Three UK-specific drags stack: the 3% additional-property SDLT surcharge, the ICR stress test that caps leverage off rent (not value), and Section 24 restricting mortgage-interest relief to a 20% credit — pushing higher-rate taxpayers toward limited-company structures. The tool substitutes your actual inputs into this relationship and shows the worked example step by step.
What inputs does the Buy-to-Let Calculator need?+
Enter Purchase price (currency), Monthly rent (currency), BTL mortgage (currency), Mortgage rate (IO) (%), Lender stress rate (%), ICR required (%) and the result updates immediately — there is no button to press. Change any value to model a different scenario in real time.
Is the Buy-to-Let Calculator free, and is my data private?+
Yes — it is completely free with no sign-up or usage limit, and it runs entirely in your browser, so the numbers you enter are never uploaded or stored on any server. It is for informational and analytical use, not financial advice.
What is the Buy-to-Let Calculator based on?+
The method follows authoritative sources: PRA SS13/16 — BTL underwriting; Finance Act §24 changes. The formula and references are shown on the page so you can verify and cite the result.
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