When you apply for a buy-to-let mortgage, lenders rarely stop at headline interest cover. They stress your rent against a higher notional rate — often 5.5% or more — to see if the deal still works if rates rise.
Debt service coverage ratio (DSCR) compares net rent to debt service under that stressed assumption. A ratio below 1.0× means rent does not cover the stressed payment; many lenders want 1.25× or higher for limited companies, and stricter bands for higher LTV.
PropDeal calculates DSCR in your Financial Verdict and lender stress panels using your entered rent, finance assumptions, and operating costs. You see pass/fail against typical institutional thresholds without rebuilding spreadsheets.
Use DSCR alongside net yield and cash flow: a deal can show positive monthly cash on your actual rate but fail lender stress — catching that before an offer protects your time and broker relationships.