Unlike DSO, CEI does not move with sales volume and it excludes invoices that are not yet due, so it isolates how well collections are working from how fast the business is growing. A CEI of 100 means everything collectible was collected; above 80 is healthy for most B2B service businesses.
Formula
CEI = (Beginning AR + Credit sales − Ending total AR) ÷ (Beginning AR + Credit sales − Ending current AR) × 100
Example: Start $380,000, invoice $420,000, end $410,000 with $290,000 current: (380 + 420 − 410) ÷ (380 + 420 − 290) = 390 ÷ 510 = 76.5.