Free UK buy-to-let tool
BTL calculator UK
Work out a UK buy-to-let deal in seconds: buy-to-let mortgage payment, rental yield, monthly cash flow, cash-on-cash return and the 145% ICR lender stress test — the same maths ACQR runs on every deal.
Buy-to-let calculator
Insurance, maintenance, voids, letting fees, other.
Cash spent on top of the deposit.
£135,000 loan at 5.25% interest only.
Lender stress test — likely passes
At a stressed rate of 5.5% and 145% ICR, lenders would want about £897 per month of rent. Indicative maximum loan on this rent: £142,947.
Indicative figures for planning. Lender criteria, tax and voids can change the outcome materially.
How to use this BTL calculator
- Enter the purchase price and the monthly rent the property should achieve.
- Set your deposit percentage — most UK BTL lenders want 25% and price better at 40%.
- Add the buy-to-let mortgage rate and term, and switch interest only on or off.
- Put purchase tax (LBTT in Scotland, SDLT in England), solicitor and lender fees and any refurbishment into buying costs.
- Read the cash flow, cash-on-cash return and stress test together — a high yield with thin cash flow is still a weak deal.
Buy-to-let calculator FAQs
What is a BTL calculator?
A BTL (buy-to-let) calculator works out whether a rental property stacks up financially. It takes the purchase price, deposit, mortgage rate and expected rent, then returns your monthly mortgage payment, rental yield, monthly cash flow and return on the cash you invest.
How is a buy-to-let mortgage payment calculated in the UK?
Most UK buy-to-let mortgages are interest only, so the monthly payment is the loan amount multiplied by the annual interest rate, divided by 12. On a repayment basis the payment also clears the capital over the mortgage term, so it is materially higher for the same loan.
What is the 145% ICR stress test?
UK buy-to-let lenders check that rent covers the mortgage with a margin. A common test is rent of at least 145% of the interest payment calculated at a stressed rate of around 5.5%, rather than your actual pay rate. This calculator shows that indicative stress test so you can see the likely maximum loan before you apply.
What is a good rental yield for a UK BTL property?
Gross yields of 6–8% are common for UK single lets, with city-centre flats often lower and multi-lets higher. Yield alone is not enough: check net yield after running costs and the monthly cash flow after the mortgage.
Does the BTL calculator include stamp duty or LBTT?
Purchase tax is entered inside buying costs. In Scotland that is LBTT plus the 8% Additional Dwelling Supplement on additional properties, which the free LBTT calculator works out for you. In England and Northern Ireland it is Stamp Duty Land Tax with its own surcharge.
Related free tools: LBTT calculator (Scotland) and rental yield calculator.
Want the full deal picture?
ACQR analyses a whole property listing — refurb, purchase tax, lender stress test, local rent benchmark, maximum offer and a clear qualify / investigate / walk-away verdict.
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