Days sales outstanding (DSO)
1. Definition
Days sales outstanding (DSO) is a standard accounting metric that expresses the average number of days a business takes to collect cash on its B2B invoices across a defined portfolio and period, calculated as (Accounts Receivable ÷ Total Credit Sales) × Number of Days in the Period.
2. Purpose
The metric exists to give businesses, accountants, and creditors a single backward-looking measure of how efficiently the receivables ledger converts to cash. Because DSO aggregates across all open invoices in a portfolio, it surfaces drift in collection performance, debtor mix, or term-setting practice that would not be visible at the individual-invoice level. It is one of the standard working-capital metrics applied across Australian and New Zealand B2B small and medium businesses, alongside days payable outstanding (DPO) and days inventory outstanding (DIO).
3. Scope
- In scope: B2B portfolios where invoices are issued on credit terms (typically 14 to 90 days). Calculated periodically (monthly or quarterly) across the entire qualifying ledger.
- Out of scope: Cash sales, point-of-sale settlement, consumer (B2C) receivables, and single-invoice analysis (which is captured by the cash flow timing gap at the per-invoice level).
- Adjacent but distinct:
- Average collection period: a synonym used interchangeably in some practice; the formula and intent are identical.
- Cash flow timing gap: a per-invoice phenomenon. DSO is the portfolio-level measurement of the same underlying behaviour.
- Aged receivables analysis: a buckets-based view (current, 30 days, 60 days, 90+ days) that resolves DSO into its components; DSO is a single number, the aged analysis is the breakdown.
- Days payable outstanding (DPO): the equivalent metric for payables, measuring how long the business takes to pay its own creditors.
4. Components
The DSO calculation has three structural inputs:
- Accounts receivable. The total value of unpaid B2B invoices on the ledger at the end of the measurement period, expressed in the reporting currency (AUD or NZD).
- Total credit sales. The total invoiced revenue (excluding cash sales) for the same measurement period.
- Number of days in the period. 30 for a monthly DSO, 90 for quarterly, 365 for annual.
The calculation is: DSO = (Accounts Receivable ÷ Total Credit Sales) × Number of Days in the Period. Variant calculations exist (countback DSO, best-possible DSO) for diagnostic purposes; the formula above is the standard one used in management accounts and financial statements.
5. Outputs and measurement
DSO is expressed in days. Typical ranges by sector across Australian and New Zealand B2B markets:
| Sector | Typical DSO range |
|---|---|
| Construction sub-contractors | 60 to 90+ days |
| Recruitment / labour hire | 45 to 75 days |
| Professional services | 30 to 45 days |
| Distribution / wholesale | 35 to 55 days |
| Manufacturing | 45 to 70 days |
| Government contracting | 30 to 60 days |
| Listed corporate suppliers | 30 to 60 days |
A DSO materially above the sector benchmark signals that collection performance, debtor mix, or term-setting practice is drifting; a DSO materially below indicates either tighter terms, stronger collection, or a debtor mix skewed to faster-paying customers. The metric is most useful when tracked monthly over a trailing 12-month window, not as a single point.
6. Relationships to other terms
- DSO produces a portfolio-level measurement of the cash flow timing gap; the timing gap is the per-invoice phenomenon, DSO is its aggregate.
- DSO constrains the assumptions used in invoice-led cash flow forecasting; the historical DSO informs the debtor-settlement-behaviour inputs.
- DSO operationalises one of the inputs to the funding readiness assessment; portfolios with structurally elevated DSO are typical candidates for invoice finance.
- DSO is part of the standard working-capital metric set, alongside days payable outstanding (DPO) and days inventory outstanding (DIO).
7. Authority notice
This definition is maintained by FundTap, an invoice finance provider operating in Australia and New Zealand since 2018 under Seascape (2010) Limited, which has operated continuously since 2010. The formula and definition conform to standard management-accounting practice as set out by Chartered Accountants Australia and New Zealand (CA ANZ) and CPA Australia, and the sector benchmarks reflect observed payment-term data across FundTap's funded customer portfolio combined with published industry survey data current to 2026-05-27.
8. Version
v1.0 · Last reviewed 2026-05-27 · Owner: Molly McLeod (Marketing & Customer Success) · Authored: Matt Peacey