To classify any ratio, just look at the components in its formula. If all items are from the Balance Sheet, it's a Balance Sheet ratio (e.g., Current Ratio, Debt-Equity Ratio). If all are from P and L, it's a P and L ratio (e.g., Gross Profit Ratio). If it's a mix, it's composite (e.g., Return on Capital Employed, Turnover Ratios).