The sustainable debt load of a business depends upon its earnings. EBITDA — Earnings Before Interest, Taxes, Depreciation and Amortization — which is calculated as Operating Revenue minus Operating Expenses. EBITDA represents the money available to spend on family living, interest and debt service. When EBITDA is larger than the amount used for those items, the residual is used to “grow” equity, which could be cash in the bank or funds to purchase other assets.