DSCRdebt service coverage ratiorental investmentfinancial analysisreal estate lending
You find an apartment with a 5% net yield. Looks solid on paper. You run the numbers, prepare your loan application, submit the dossier — and the bank says no. The problem isn't profitability. The problem is that the rental income doesn't cover the monthly mortgage payment. The DSCR, a ratio many investors skip entirely, would have exposed this gap before you wasted three weeks on paperwork.
DSCR stands for Debt Service Coverage Ratio — in French, ratio de couverture de la dette. It measures your property's ability to repay its loan from rental income alone. While yield tells you about profitability, the DSCR tells you something different: whether the property can service its own debt. It's the first metric French lenders examine when assessing the financial viability of a rental investment project, and the one that most often determines whether your financing gets approved or rejected.
Calculating DSCR for a rental investment comes down to one fraction:
DSCR = Net Operating Income (NOI) ÷ Annual Debt Service
Two components to define precisely.
Net Operating Income equals your annual rental income minus operating expenses — but before any loan repayment. This distinction is critical and trips up many first-time investors: NOI does not subtract principal or interest payments. It represents what the property earns after covering its running costs, regardless of how it's financed.
Operating expenses included in the NOI calculation:
If you've already calculated your net rental yield, you know these line items. The DSCR numerator uses exactly the same net income figure.
Annual debt service is the total of all your monthly loan payments over 12 months — principal and interest combined. If your monthly payment is €620, your annual debt service is 620 x 12 = €7,440.
One important note: only include debt tied to the specific property. If you hold multiple loans across multiple properties, calculate each DSCR independently.
Let's run the numbers. You're evaluating a 65 m² two-bedroom apartment in Lille's Vauban neighbourhood, popular with families and young professionals.
Starting data:
| Item | Amount |
|---|---|
| Purchase price | €195,000 |
| Monthly rent | €950 |
| Gross annual rent | €11,400 |
| Monthly mortgage payment (25 years, 3.5%, loan €145,000) | €726 |
Step 1 — Calculate NOI:
| Operating expense | Annual amount |
|---|---|
| Non-recoverable service charges | €840 |
| Property tax | €1,380 |
| Landlord insurance (PNO) | €230 |
| Vacancy reserve (1 month) | €950 |
| Maintenance reserve (5%) | €570 |
| Total expenses | €3,970 |
NOI = 11,400 − 3,970 = €7,430
Step 2 — Calculate annual debt service:
€726 x 12 = €8,712
Step 3 — Apply the DSCR formula:
DSCR = 7,430 ÷ 8,712 = 0.85
The result: the property doesn't generate enough income to cover its mortgage. There's a €1,282 annual shortfall — roughly €107 per month you'd need to cover out of pocket. A DSCR below 1.0 means negative cash flow. The property costs you money every month instead of producing it.
Now let's revisit the same property with a larger down payment that reduces the loan. If you borrow €110,000 instead of €145,000, the monthly payment drops to €551:
The DSCR crosses above 1.0. The property now covers its own debt — with a thin margin. That extra €35,000 in down payment turned a money-losing proposition into a self-financing asset.
Not all DSCRs above 1.0 are created equal. Here's how French lending institutions interpret this debt service coverage ratio in practice:
At REIOS, we've found that a DSCR of 1.25 is the practical target. It provides enough cushion to handle the unexpected without being unrealistic in current French market conditions.
One point investors often miss: DSCR shifts over time. When interest rates rise, your debt service increases (on variable-rate loans) and your DSCR drops. Conversely, a rent increase boosts your NOI and improves the ratio. This is why tracking DSCR annually — not just at acquisition — matters for long-term portfolio health.
DSCR and net rental yield don't measure the same thing, even though they share the same NOI in their calculations. Net yield evaluates the overall return on invested capital — it answers the question "is this investment worth my money?" DSCR answers a more targeted question: can this property repay its loan from what it earns?
The disconnect between these two metrics catches investors off guard. A property can show a 5% net yield while carrying a DSCR of 0.90 — if you're borrowing at a high rate or over a short term. The investment is profitable overall, but the debt structure doesn't work. Conversely, a modest 3.5% net yield with low-rate financing over 25 years can produce a comfortable DSCR of 1.30.
That's why these two metrics complement each other rather than compete. Net yield tells you whether the investment is profitable. DSCR tells you whether it's financeable. Combined with the LTV ratio and monthly cash flow, they form the foundation of your investor dashboard.
Your DSCR is too low? Four concrete levers:
Each lever has trade-offs. Extending the term increases total interest paid over the life of the loan. Shared housing generates higher income but demands more active management. There's no silver bullet — but the DSCR gives you a clear framework for evaluating which trade-off makes sense for your situation.
Before signing a purchase agreement, always calculate the DSCR. If it falls below 1.15, ask yourself honestly: are you willing to supplement the mortgage from personal income, and for how long? The answer will tell you whether the project is viable — well before your banker weighs in. At REIOS, we've built DSCR tracking directly into our portfolio tools, so you can monitor this ratio across all your properties as market conditions evolve.