Debt Service Coverage Ratio Calculator
Find UK interest coverage and debt service ratio.
What this calculator does
This DSCR calculator measures whether income covers debt repayments with room to spare. Enter net operating income and annual debt service, and it returns the debt service coverage ratio, along with a table showing what income would be needed at various coverage levels and how much buffer you currently have.
A ratio of 1.0 means income exactly covers repayments with nothing left for a difficult quarter, which is why lenders insist on a cushion. DSCR is the central number in commercial lending decisions and frequently determines facility size before loan-to-value becomes the binding constraint.
When to use it
Run it before approaching a lender, because it tells you what facility size your income can realistically support. Working backwards from net operating income at the lender's required ratio gives maximum annual debt service and from there a maximum loan — a far better starting position than naming a figure and being cut back.
It is also the number to monitor if you already have covenants in place. Checking quarterly rather than discovering a breach at a compliance date gives you months of warning. And it is the right tool for testing a downside: knowing income can fall 9 percent before breach turns an abstract clause into a concrete risk tolerance.
Understanding the inputs
Net operating income is revenue less operating costs, before interest, tax, depreciation, and amortisation. For property, include a realistic void allowance and a management fee even where you manage it yourself, because a lender will impute both. Understating costs inflates income and produces a ratio your lender will not accept.
Annual debt service is the total of twelve monthly payments across all facilities being tested, capital as well as interest. Include any required reserve contributions if the facility agreement counts them. Where you are testing a proposed facility, calculate the repayment first and bring the annual total here — and consider running it again at a stressed rate.
How is this calculated?
DSCR = Net Operating Income / Total Debt Service. DSCR > 1.25 is typically required by lenders.
A worked example
A business generates £280,000 of net operating income against £205,000 of annual debt service, giving a DSCR of about 1.37. Against a 1.25 covenant that is reasonably comfortable — the maximum debt service permitted is £224,000, leaving £19,000 of headroom.
Expressed as tolerance, income could fall to £256,250 before breaching, a drop of about 8.5 percent. Stress-tested at two points above the current rate, annual debt service might rise toward £235,000, which would put the ratio at 1.19 and inside breach territory. That second calculation is the one lenders run and borrowers often skip.
Limitations and assumptions
The ratio is a snapshot from a single period, and lenders normalise net operating income in ways borrowers rarely anticipate — imputing management fees, adjusting below-market rents, or adding a void allowance. The DSCR your lender calculates is commonly lower than the one you calculate yourself.
It says nothing about timing within the year either. A business with sound annual coverage can still miss a payment in a seasonal trough, since DSCR is annual while obligations are monthly. It also excludes capital expenditure, which sits outside net operating income but still consumes cash. Read it alongside a monthly cash flow forecast rather than in isolation.
Common Questions
- What DSCR do UK lenders require?
- Commercial lenders typically set a minimum of 1.20 to 1.30. Commercial investment property often requires 1.25 or more, and lenders may also stress-test at a higher notional interest rate than the one you are paying. Trading businesses are usually assessed on adjusted EBITDA rather than property-style net operating income.
- What is the difference between DSCR and interest cover?
- DSCR measures net operating income against the full annual payment including capital repayment. Interest cover measures it against interest alone, which is a much easier test. UK facility agreements often include both, and the capital-inclusive test is usually the one that bites first as a loan amortises.
- How do lenders stress-test the ratio?
- By recalculating coverage at a notional rate above your actual rate — commonly the pay rate plus 2 percent, or a floor rate set by the lender. On a variable facility this determines how much you can borrow, and it is why a loan sized on today's rate is often smaller than the arithmetic suggests.
- What happens if I breach a covenant?
- It is technically an event of default even when every payment has been made on time. In practice lenders usually grant a waiver in return for a fee, additional security, or a cash sweep. But it hands the lender control at precisely the moment your position is weakest, which is why headroom is worth defending.
- How much can income fall before I breach?
- The buffer is easy to work out. At a DSCR of 1.37 against a 1.25 covenant, net operating income can fall about 9 percent before breaching. That tolerance is a more useful figure than the ratio, because it can be compared directly against how volatile your income actually is.
- How does DSCR determine my borrowing capacity?
- Lenders work backwards from it. Divide net operating income by the required ratio to find maximum annual debt service, then convert that into a facility size at the offered rate and term. This frequently binds before loan-to-value does, which is why a strong valuation does not always deliver the loan you expected.
- Can I improve the ratio without repaying debt?
- Three routes. Raise net operating income through revenue or cost reduction, which is slow but durable. Extend the term, which cuts annual debt service immediately but increases total interest. Or refinance at a lower rate. Lenders regard an income improvement as far more convincing than a term extension.
- Do lenders look at my other borrowings too?
- Increasingly yes, particularly where directors have given personal guarantees. A global coverage test includes all group and sometimes personal obligations, not just the facility being assessed. Since guarantees are standard for UK small business lending, expect your wider position to form part of the assessment.
- How often is the covenant tested?
- Usually quarterly, sometimes semi-annually, against a rolling twelve-month period, with a compliance certificate signed by a director. Testing on a rolling basis means one poor quarter affects the ratio for a full year, so monitoring monthly rather than waiting for the test date gives you time to respond.