About BTL Insight
Free, independent Buy to Let tools for UK landlords and property investors.
BTL Insight is a free, independent set of Buy to Let tools for UK landlords and property investors. The aim is simple: make the numbers behind a rental property easy to check, so people can make better decisions before they spend money on surveys, legals or a mortgage application.
How the tools are built
Buy to let has a lot of moving parts, and most free calculators online oversimplify them. These tools are built to reflect how the lending actually works: interest cover ratios and stress rates for affordability, the correct stamp duty bands and surcharges for each UK nation, and the true cost of a mortgage once fees are included. Lenders use different ratios and stress rates, so no calculator can match every lender exactly. The aim is a realistic figure based on typical lender criteria, rather than an oversimplified one.
Where the numbers come from
The calculators use published, official sources rather than estimates:
- Stamp duty: HMRC (SDLT), Revenue Scotland (LBTT) and the Welsh Revenue Authority (LTT).
- Affordability: the interest cover ratio and stress rate approach lenders apply under Prudential Regulation Authority underwriting standards.
- Interest rates: the Bank of England base rate where relevant.
What this site is not
BTL Insight is an information service. It is not a mortgage broker, it does not sell mortgages, and nothing on the site is financial advice or a personal recommendation. The tools cannot see your full financial picture, and lender criteria change often, so the results should be treated as a guide. For advice on your own situation, speak to a qualified mortgage adviser, who can confirm the figures and recommend a product that fits.