Calculating Debt Service Capacity: Formula, Example, Bank View (2026)

Calculating debt service capacity means testing whether a company can cover interest and principal on its loans sustainably out of operations. You derive the extended cash flow, deduct capital expenditure and owner distributions to arrive at the debt service limit (the maximum debt service the business can carry), and divide the actual debt service by that limit to get the utilisation ratio. That ratio is the number that matters in a bank conversation. The perspective matters too: banks calculate it not only for the last closed year but across the planned years of the financing term.

A note on terminology for readers outside Germany: this is the corporate calculation, known as Kapitaldienstfähigkeit. It differs from the consumer mortgage version, where household income is set against living costs, and which dominates most search results for the term.

The three quantities

Debt service itself is the simple part: debt service = principal + interest. The work sits in the limit.

Step 1: Extended cash flow

The extended cash flow starts from net income and corrects every item that reduces earnings without costing cash, and vice versa:

• + Net income (or - net loss)
• + Depreciation and amortisation - write-ups
• + Increase in long-term provisions - decrease
• + Interest and principal on existing debt service
• + Non-cash expenses
• - Non-cash income

The fourth item often surprises people: existing debt service is added back, because the limit is meant to represent total capacity for debt service, not what remains after servicing legacy loans.

Step 2: The debt service limit

Debt service limit = extended cash flow - capital expenditure - owner distributions

What gets deducted is whatever the company needs in order to remain what it is: replacement capex and shareholder distributions. Understate these and you produce a capacity figure that fails in year three for want of machinery.

Worked example

A company applies for a 1.0 million euro loan over 8 years at 4.5 percent. All figures in thousands of euros:

Future debt service is the existing 340 plus the new loan (principal 125, interest around 45, so 170), giving 510. The utilisation ratio is 510 / 730 = 0.70.

How banks read the ratio

Lending practice uses broad reference bands for the utilisation ratio, which vary by institution and internal rating model:

At 0.70, the example sits exactly on the boundary between satisfactory and adequate. Financeable, but without headroom.

Why the static calculation hides the problem

The calculation above rests on a single year’s earnings. That is its weakness: the financing runs eight years and earnings will not be exactly 480 in any of them. Suppose net income falls by 150, because a major customer reduces volume. Extended cash flow drops to 1,030, the limit to 580, and the utilisation ratio jumps to 510 / 580 = 0.88. “Satisfactory” becomes “critical” without anything changing about the loan.

That sensitivity is the genuinely useful information, and it does not come from one more precise calculation but from several. Running debt service capacity across the term and in variants requires integrated financial planning, where earnings, balance sheet and cash flow are connected, and the ability to change one assumption and see the result immediately.

When the bank will ask regardless

Disclosure is not a matter of negotiation. Under § 18 (1) of the German Banking Act (KWG), a credit institution may only grant a loan exceeding 1,500,000 euros or 10 percent of its own core capital if it obtains disclosure of the borrower’s economic circumstances, in particular by presentation of annual financial statements. For existing credit relationships, disclosure is ongoing and required at least annually. Below the threshold, banks request the same documents in practice, driven by their own risk management rather than by that provision.

Being able to calculate the figure yourself is an advantage going into that conversation: you know the number before the bank names it, and you can explain the assumptions behind it. What else is expected is covered in the article on preparing for a bank meeting.

Frequently asked questions

What is the difference between the debt service limit and debt service coverage?

The limit is an absolute amount, the maximum serviceable debt in euros. Coverage expresses available cash flow relative to actual debt service, making it the inverse of the utilisation ratio. Both describe the same fact from opposite directions.

Which utilisation ratio is still acceptable?

Common reference points treat up to 0.7 as unproblematic and 0.8 and above as critical. What decides is the bank’s internal rating model and the stability of earnings: a company on long-term contracts tolerates a higher ratio than one running volatile project business.

Is it calculated from the annual accounts or from the plan?

Both. The accounts provide the historical base, the plan the statement about the financing term. For a new loan the planned figures matter more, because the loan will be serviced out of future rather than past surpluses.

How do leasing and hire purchase affect the calculation?

Lease payments are an expense in the P&L and reduce earnings, but they do not appear as debt service. Banks frequently strip them out and add them to debt service to make the company comparable with debt-financed peers. If you calculate it yourself, make that treatment transparent.

What if the ratio comes out too high?

The four levers follow directly from the formula: improve earnings, stretch capex, reduce distributions, or lengthen the amortisation profile. The last is fastest but raises the total cost of the financing. Which combination works can only be calculated, not estimated.