"How much debt can this company support?" is one of the more deceptively difficult questions in a leveraged finance or private equity interview, because most candidates reach for a single leverage multiple and stop there — when the interviewer is actually testing whether you know that a leverage multiple is only one of three constraints on debt capacity, and often not even the tightest one. This article walks through, step by step, exactly how to structure an answer to a debt capacity interview question: what data to ask for, which formulas to apply in what order, and how to identify which constraint actually binds.
The framework below mirrors the exact sequence used in the Debt Capacity case study, which works through a full numerical example using an 80 million EBITDA company and a set of realistic lender terms. If you haven't worked through that case yet, it's worth doing so alongside this walkthrough — this article explains the reasoning behind each step, while the case gives you the numbers to practice on.
Step 1: Get the Data You Actually Need
Before calculating anything, you need seven pieces of information, and a well-prepared candidate will ask for any that aren't given rather than assuming them: EBITDA, the interest rate on the proposed debt, the maximum total leverage multiple the lender is willing to underwrite, the minimum interest coverage ratio required by the covenant package, the mandatory annual amortization rate, Cash Flow Available for Debt Service (CFADS), and the minimum debt service coverage ratio (DSCR) the credit agreement requires. Missing any one of these means you can only calculate part of the picture — for instance, without CFADS and a minimum DSCR, you can size a leverage-based and interest-coverage-based ceiling, but you can't test the cash flow constraint that, as explained in What Is a Leveraged Buyout (LBO)?, is usually the one that actually governs.
Interviewers sometimes withhold one or two of these inputs deliberately, specifically to see whether you notice the gap and ask for it, rather than silently assuming a number. Flagging "I'd need the mandatory amortization rate to size the cash flow test properly — can you give me that, or should I assume a standard Term Loan B structure with minimal amortization?" is exactly the kind of clarifying question that signals you understand the mechanics rather than just the formulas.
Step 2: Calculate the Leverage-Based Ceiling First
Start with the simplest and loosest constraint: Debt Capacity (Leverage) = EBITDA × Maximum Total Leverage Multiple. If EBITDA is 80 million and the lender's guideline is 5.5x, this gives you 440 million. This is the number most people mention first because it's the headline term everyone quotes — "it's a 5.5x deal" — but explicitly frame it in your answer as a starting point, not the final answer. Say something like "that's the ceiling implied by the leverage guideline alone, but I want to check it against interest coverage and cash flow before I treat it as the actual capacity" — this signals to the interviewer immediately that you know more tests are coming.
Step 3: Calculate the Interest Coverage-Based Ceiling
Next, work out how much debt the interest coverage covenant allows. First find the maximum interest expense the company can carry: Maximum Interest Expense = EBITDA / Minimum Interest Coverage Ratio. With EBITDA of 80 million and a 3.0x minimum coverage ratio, that's 26.7 million of interest. Then convert that interest ceiling into a debt ceiling: Debt Capacity (Interest Coverage) = Maximum Interest Expense / Interest Rate. At an 8% interest rate, 26.7 million of maximum interest supports 333.3 million of debt.
Notice that this ceiling — 333.3 million, or roughly 4.2x EBITDA — is already tighter than the 440 million leverage-based ceiling from Step 2. Point this out explicitly in your answer; it's the first piece of evidence that the headline leverage multiple overstates what the company can actually support, and it sets up the logic for why you need a third test.
Step 4: Calculate the Cash Flow (DSCR-Based) Ceiling
This is the step most candidates either skip or get wrong, and it's usually the one that matters most. Start by finding the maximum total debt service — interest plus mandatory amortization — the business's cash flow can support: Maximum Debt Service = CFADS / Minimum DSCR. With CFADS of 42 million and a minimum DSCR of 1.2x, that's 35.0 million of maximum annual debt service.
Now convert that debt service ceiling into a debt balance. Debt service as a percentage of the debt balance equals the interest rate plus the mandatory amortization rate — in this example, 8% interest plus 5% amortization, or 13.0% combined. Debt Capacity (DSCR) = Maximum Debt Service / (Interest Rate + Amortization Rate) = 35.0 million / 0.13, which works out to roughly 269.2 million.
Walk through out loud why this number is so much lower than the other two: CFADS already strips out capital expenditures, cash taxes, and working capital changes that EBITDA ignores entirely, and the debt service figure includes mandatory principal repayment on top of interest — neither the leverage test nor the interest coverage test accounts for amortization at all. That combination is exactly why the cash flow test tends to be the most conservative of the three, and interviewers want to hear you explain the "why," not just produce the number.
Step 5: Identify the Binding Constraint and State It Clearly
Once you have all three ceilings — 440.0 million (leverage), 333.3 million (interest coverage), and 269.2 million (DSCR) — the effective debt capacity is simply the minimum of the three: 269.2 million in this example. Say this explicitly and translate it back into a leverage multiple so the interviewer can sanity-check it against the original guideline: 269.2 million divided by 80 million EBITDA is approximately 3.4x — nearly two full turns of leverage below the 5.5x the lender initially quoted.
This is the punchline interviewers are listening for: the gap between the advertised leverage multiple and the actual serviceable debt level. Stating it as a clean, quantified comparison — "the lender's guideline suggested 5.5x, but once I test interest coverage and cash flow debt service, the real ceiling is closer to 3.4x, driven by the DSCR covenant" — demonstrates exactly the kind of skepticism a leveraged finance analyst is expected to apply before a deal gets priced.
Common Follow-Up Questions and How to Handle Them
Interviewers rarely stop at the base calculation. Be ready for at least three follow-ups, and think through the mechanics rather than memorizing answers:
"What happens if CFADS falls in a downturn?" Re-run the DSCR test with a lower CFADS figure and show that the debt ceiling falls roughly proportionally — if CFADS drops from 42 million to 30 million, the DSCR-based ceiling falls from 269.2 million to roughly 192.3 million. The point to make explicitly is that debt capacity should be stress-tested against a downside case, not sized once off a base case and left alone, a discipline explored further in How to Calculate the Maximum Price to Pay for an LBO Target.
"How would a back-loaded amortization schedule change the answer?" If mandatory amortization is minimal in the early years — the classic Term Loan B structure, with roughly 1% annual amortization and a bullet at maturity, rather than a straight 5% per year — near-term debt service drops, which raises the near-term DSCR-based ceiling. This is exactly why sponsor-backed leveraged buyouts almost always use Term Loan B structures rather than more heavily amortizing facilities: it supports more leverage during the hold period, at the cost of shifting risk to a large repayment obligation at maturity. The mechanics of how different debt tranches are structured and priced are covered in more depth in the Debt Structures in an LBO case and its companion LBO Debt Structures Explained article.
"Why would a lender add a total leverage covenant on top of a senior leverage covenant?" Because a senior leverage covenant only caps the senior tranche — it says nothing about how much subordinated or mezzanine debt the sponsor layers on beneath it. A total leverage covenant caps the combined balance, protecting the senior lender's effective coverage and recovery prospects from being eroded by additional junior debt that technically doesn't touch the senior covenant at all.
How This Fits Into the Rest of an LBO Model
Once you've established the effective debt capacity, the next natural question — and often the next one asked in the same interview — is how that debt figure flows into the rest of the deal. The debt capacity number becomes the debt side of the Sources and Uses table, and whatever the purchase price doesn't cover with that debt has to come from the sponsor's equity check, a mechanic practiced directly in the Sources and Uses Table case. From there, the size of that equity check drives the Multiple of Money and IRR the sponsor can expect if the deal performs as modeled — the exact calculation covered in How to Answer "Walk Me Through an LBO" in a PE Interview and practiced end-to-end in the Paper LBO case, which asks you to reason through an entire buyout — leverage, growth, exit — without a spreadsheet.
Debt capacity also has a direct relationship with entry pricing. A sponsor who can only support 3.4x of leverage instead of the 5.5x a lender initially floats has to write a larger equity check for the same purchase price, which changes how aggressively that sponsor can bid in an auction process — a dynamic explored further in IRR-based pricing in private equity and in the Entry and Exit Multiple case, which looks at how leverage and exit assumptions together shape the return a sponsor ultimately earns.
Sensitivity: How Each Assumption Moves the Answer
A strong candidate doesn't just produce the three ceilings once — they can explain, without recalculating from scratch, which direction each ceiling moves if a single assumption changes. This is worth rehearsing separately from the base calculation, because interviewers frequently probe sensitivity as a follow-up rather than asking for it upfront.
Raising the interest rate lowers the interest coverage-based ceiling directly — a higher rate means less debt supports the same maximum interest expense — and it also lowers the DSCR-based ceiling, since a higher interest rate increases the combined interest-plus-amortization percentage used in that calculation. Notice that the leverage-based ceiling doesn't move at all when the interest rate changes, since that formula never references the interest rate in the first place. This is a useful thing to say out loud, because it reinforces exactly why the leverage multiple alone is such an incomplete measure of debt capacity: it's structurally blind to financing cost.
Tightening the minimum interest coverage ratio — say, from 3.0x to 4.0x — lowers the maximum interest expense the company can carry, which lowers the interest coverage-based ceiling proportionally. Tightening the minimum DSCR covenant has the same directional effect on the cash flow-based ceiling: a stricter minimum DSCR shrinks the maximum debt service the business is allowed to carry, which shrinks the implied debt balance. In both cases, lenders tighten these covenants specifically when they perceive more risk in the credit — a more cyclical business, a less experienced sponsor, or a softer macro backdrop typically means tighter coverage requirements and, mechanically, a lower effective debt capacity even if EBITDA and CFADS stay exactly the same.
Finally, CFADS itself is usually the most volatile input of the three, because unlike EBITDA it already reflects capital expenditure, cash taxes, and working capital movements — all of which fluctuate meaningfully year to year in a way EBITDA alone doesn't fully capture. This is precisely why the DSCR-based ceiling tends to be the constraint most likely to bind, and the one most worth stress-testing against a downside scenario rather than accepting at face value from a single base-case projection.
A Quick Reference: The Three-Step Debt Capacity Test
If you only remember one structure to reproduce under interview pressure, remember this sequence: calculate the leverage-based ceiling first because it's simplest, then the interest coverage-based ceiling because it introduces the actual cost of debt, then the DSCR-based ceiling because it captures true cash availability including mandatory amortization — and finally, take the minimum of the three and translate it back into an implied leverage multiple so you can compare it directly against the lender's original guideline. That last step — stating the gap between the quoted multiple and the effective capacity, and naming which covenant is responsible for that gap — is what separates a candidate who can do arithmetic from one who understands credit analysis.
To practice this exact sequence against a full worked example with real numbers, walk through the Debt Capacity case — it's built around precisely the structure described above, and the model answer shows each of the three ceilings calculated in order, with the binding constraint identified and explained.