See what percentage of collectible receivables you collected during the period.
Collection Effectiveness Index (CEI) measures how effectively a business collected the accounts receivable that was available for collection during a given period. It answers: of the receivables that could have been collected, what share was collected?
Unlike day-based metrics such as DSO, CEI is a percentage. It focuses on collectible balances rather than how long sales remain outstanding.
Amount collected = Beginning AR + Credit Sales − Ending Total AR
Amount available for collection = Beginning AR + Credit Sales − Ending Current AR
CEI = (Amount collected ÷ Amount available for collection) × 100
Ending current AR is the part of ending receivables that is still within terms. Subtracting it from beginning AR plus credit sales leaves the pool that was eligible to collect. Subtracting ending total AR leaves what was actually collected.
Example: Beginning AR $100,000, credit sales $500,000, ending total AR $120,000, ending current AR $80,000.
Amount collected = $100,000 + $500,000 − $120,000 = $480,000
Amount available = $100,000 + $500,000 − $80,000 = $520,000
CEI = ($480,000 ÷ $520,000) × 100 ≈ 92.3%. Uncollected eligible receivables = $40,000.
CEI measures collection of receivables that were available to collect—excluding ending balances that are still current. A higher CEI generally indicates that a greater percentage of collectible receivables was collected during the period.
Do not treat CEI as a letter grade. Industry terms, customer mix, write-offs, and seasonality can all change how you read the same percentage. Track CEI over time with consistent inputs for the most useful signal.
Days Sales Outstanding (DSO) estimates how many days of credit sales remain in accounts receivable. Collection Effectiveness Index estimates what share of available receivables was collected. One is a time-based stock measure; the other is a period collection percentage.
Use the DSO Calculator when you want days outstanding. Use this calculator when you want the percentage of collectible AR that was collected. Many teams review both.
CEI isolates collection results from receivables that were not yet due. That makes it useful when ending AR includes a large current balance that should not be counted against collection performance. Tracking CEI alongside DSO, aging, and turnover helps separate timing, aging mix, and collection yield.
Compare days outstanding with the DSO Calculator, aging buckets with the AR Aging Calculator, turnover with the Accounts Receivable Turnover Calculator, and days to collect with the Average Collection Period Calculator. Check a single invoice with the Days Past Due Calculator.