Buy-to-let cash flow calculator for UK landlords
Enter the price, the rent and the mortgage rate to see the net rental yield, the cash-on-cash return and whether the deal passes a lender's interest cover test. Stamp duty and Section 24 tax are worked out for you.
Start analysing deals free →The figures lenders and accountants ask about
The fields use the terms that UK lenders, accountants and sourcers use.
Stamp duty
Standard rates, the 5% additional-property surcharge, first-time buyer relief and the company rules. A company running a rental business claims relief and pays the same surcharge rates, while the 17% flat rate applies to a company that does not qualify. England and Northern Ireland, with Scotland and Wales flagged. Rates checked on 10 October 2026.
Lender interest cover test
Interest cover is tested at a lender stress rate (5.5% unless you change it), not your actual rate, against a pass mark of 125% for basic-rate and company borrowers or 145% for higher and additional-rate. Lenders vary, so you can change both. You also see the largest loan the rent supports.
Limited company or personal name
Compares net cash flow and stamp duty for both, including the Section 24 limit on finance-cost relief for personal ownership.
Try your first buy-to-let deal
You need the purchase price, the rent and the mortgage rate. It is free to use. Sign in only when you want to see and save your results.
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