Debt Service Coverage Ratio (DSCR) in Commercial Real Estate
The Debt Service Coverage Ratio (DSCR) is the single most important metric in commercial real estate lending. It measures a property's ability to cover its debt obligations from operating income — and it determines whether a lender will approve your loan.
The Formula
DSCR = Net Operating Income (NOI) ÷ Annual Debt Service
DSCR = Net Operating Income (NOI) ÷ Annual Debt Service
Annual Debt Service is the total of all principal and interest payments due in a 12-month period.
A DSCR of 1.0 means the property generates exactly enough income to cover its debt. A DSCR of 1.25 means it generates 25% more income than needed — providing a cushion for vacancies, expense increases, or interest rate changes.
What DSCR Do Lenders Require?
Minimum DSCR requirements vary by lender type, property class, and loan program:
| Lender Type | Typical Minimum DSCR |
|---|---|
| Conventional bank | 1.20 – 1.25x |
| SBA 7(a) / 504 | 1.15 – 1.25x |
| CMBS / conduit | 1.20 – 1.30x |
| Life insurance company | 1.25 – 1.35x |
| Bridge / hard money | 1.05 – 1.15x |
Most institutional lenders target 1.25x as their floor. Anything below that requires compensating factors — additional collateral, a larger down payment, or a personal guarantee.
Calculating Annual Debt Service
Annual debt service depends on three variables:
- Loan amount — the principal borrowed
- Interest rate — fixed or floating; use the note rate, not the APR
- Amortization period — typically 20–30 years for commercial loans
For a simple interest calculation (interest-only loan):
Annual Debt Service = Loan Amount × Interest Rate
Annual Debt Service = Loan Amount × Interest Rate
For a fully amortizing loan, use the standard mortgage payment formula or a financial calculator. The 1DIAS Debt Service Calculator handles both scenarios.
Practical Example
A 20,000 SF office building generates:
- NOI: $180,000/year
- Loan amount: $1,500,000
- Interest rate: 6.5%
- Annual debt service (interest-only): $97,500
DSCR = $180,000 ÷ $97,500 = 1.85x
DSCR = $180,000 ÷ $97,500 = 1.85x
This deal comfortably clears most lender thresholds. Now stress-test it: what if vacancy rises and NOI drops to $130,000?
DSCR = $130,000 ÷ $97,500 = 1.33x
DSCR = $130,000 ÷ $97,500 = 1.33x
Still above 1.25x — the deal survives a moderate stress scenario.
Why DSCR Matters Beyond Loan Approval
DSCR is not just a lender metric. It is a risk indicator for investors and brokers:
- A DSCR below 1.10x signals that any vacancy or expense increase could create negative cash flow
- A DSCR above 1.50x suggests the property may be under-leveraged — there may be room to refinance and extract equity
- Comparing DSCR across multiple deals in your pipeline helps prioritize which opportunities to pursue
How 1DIAS Calculates Debt Service
The 1DIAS Debt Service Calculator computes:
- Annual debt service from loan amount and interest rate
- Monthly payment (annual ÷ 12)
- DSCR when paired with your NOI from the Underwriter
All three calculators in 1DIAS are designed to work together. Run the Underwriter first to establish NOI, then carry that number into the Debt Service Calculator to confirm the deal pencils at your target leverage.
Key Takeaways
- DSCR is the lender's primary credit metric — know it before you call the bank.
- Always stress-test DSCR at a 10–15% NOI reduction to simulate vacancy or expense spikes.
- Interest-only loans produce lower debt service (higher DSCR) but no principal paydown — understand the trade-off.
- Use 1DIAS to run multiple leverage scenarios in seconds and save the best one to your Deal History.
Stress-test your next deal's debt service in real time with the 1DIAS Debt Service Calculator [blocked].