Key Points
- DSO equals trade receivables divided by revenue, multiplied by 365 (or the number of days in the period).
- A sudden increase in DSO without a corresponding change in credit terms often signals collection problems or revenue recorded before the customer accepted the goods.
- Most mid-market European manufacturers report DSO between 40 and 70 days, while wholesale distributors frequently exceed 80 days.
- Auditors use DSO as an analytical procedure under ISA 520, and an unexplained movement of more than 10 days year-on-year warrants investigation.
What is Receivable Days / DSO?
The formula is trade receivables at the reporting date divided by revenue for the period, multiplied by the number of days in the period. A full-year calculation uses 365 days. The result tells the auditor how long, on average, revenue sits as an unpaid receivable before the entity collects cash.
ISA 520.5 requires the auditor to develop an expectation when using analytical procedures as substantive procedures. For DSO, that expectation draws on four inputs: prior-year DSO, the entity's stated credit terms, industry benchmarks, and any known changes in customer mix or payment behaviour. ISA 520.7 then requires the auditor to investigate relationships that are inconsistent with the expectation. A 15-day jump in DSO while credit terms stayed at 30 days net is inconsistent. The auditor traces the cause: did the entity extend informal credit to a struggling customer, or did revenue get recognised under IFRS 15.46 before the performance obligation was fully satisfied?
DSO also feeds into the working capital analysis and the current ratio. An entity reporting strong revenue growth alongside rising DSO may be recognising revenue faster than it collects, a pattern that can mask liquidity pressure.
Worked example: Bergström Skog AB
Client: Swedish forestry and paper company, FY2025, revenue EUR 75M, IFRS reporter. The engagement team is performing analytical procedures on Bergström's receivables. Standard credit terms are 45 days net.
Step 1 — Extract the inputs
Bergström's draft statement of financial position shows trade receivables of EUR 13.7M at 31 December 2025. Revenue for the year is EUR 75M. Prior-year trade receivables were EUR 10.2M on revenue of EUR 68M.
Step 2 — Calculate DSO
Current year: (EUR 13.7M / EUR 75M) x 365 = 66.7 days. Prior year: (EUR 10.2M / EUR 68M) x 365 = 54.8 days. The increase is 11.9 days year-on-year.
Step 3 — Investigate the movement
The receivables ageing reveals that EUR 3.1M (22.6% of the balance) is past due by more than 60 days, up from EUR 0.9M (8.8%) in the prior year. Two pulp customers in the construction sector account for EUR 2.4M of the overdue balance. Management states that both customers are disputing delivery quantities on Q4 shipments.
Step 4 — Assess the ECL impact
The extended DSO and rising past-due balances require the team to evaluate whether the provision matrix for expected credit losses reflects the deterioration. The entity's matrix applies a 2% loss rate to receivables 61 to 90 days past due. Given the concentration in two customers, the team tests whether individual assessment under IFRS 9.B5.5.4 is more appropriate than the collective matrix approach for these exposures.
Conclusion: DSO of 66.7 days is 11.9 days higher than the prior year and 21.7 days beyond standard credit terms, driven by two disputed balances that require both revenue recognition and ECL reassessment before the receivables balance is defensible.
Why it matters in practice
- Teams often calculate DSO using total revenue including cash sales, which understates the metric. The numerator (trade receivables) reflects credit sales only, so the denominator should exclude cash revenue to produce a meaningful collection metric.
- The link between DSO and revenue recognition is frequently under-documented. ISA 240.A46 identifies revenue-related fraud risks including fictitious revenue that inflates receivables without corresponding cash inflows. A rising DSO alongside stable credit terms is one of the most visible indicators of this risk.
Receivable days vs payable days
| Dimension | Receivable days (DSO) | Payable days (DPO) |
|---|---|---|
| What it measures | Average days to collect cash from customers | Average days the entity takes to pay its suppliers |
| Formula | Trade receivables / revenue x 365 | Trade payables / cost of sales x 365 |
| Direction of concern | Rising DSO signals slower collection or revenue quality issues | Rising DPO may signal liquidity pressure or deliberate cash management |
| Audit focus | Test receivables ageing, credit terms, ECL adequacy, cut-off | Test payables completeness, cut-off, supplier confirmations, and accrual accuracy |
| Going concern link | Extended DSO reduces cash inflows and can trigger covenant breaches | Extended DPO beyond supplier terms risks supply disruption and legal claims |
Both metrics feed into the cash conversion cycle, which measures the total number of days between paying for inventory and collecting cash from customers.
Related terms
Frequently asked questions
How do I calculate receivable days for a company with seasonal revenue?
Annualised DSO using year-end receivables can be misleading when revenue concentrates in specific quarters. ISA 520.A14 acknowledges that data relationships may be less predictable at interim periods. Calculate DSO using the final quarter's revenue annualised (Q4 revenue x 4) alongside the full-year calculation, then compare both to prior-year equivalents. The gap between the two figures reveals how much of the year-end receivable balance reflects seasonal timing rather than slow collection.
Does DSO apply to long-term construction contracts?
For contracts accounted for over time under IFRS 15.35, revenue recognised before billing creates a contract asset, not a trade receivable. Including contract assets in the DSO numerator inflates the metric. Separate the analysis: calculate DSO on billed receivables only, then monitor contract assets as a distinct balance with its own ageing and conversion timeline.
When should an increase in DSO trigger a going concern assessment?
ISA 570.A3 lists the inability to pay creditors on due dates as an indicator of going concern doubt. If rising DSO forces the entity to delay its own payables (increasing payable days simultaneously), the cash conversion cycle is deteriorating. The auditor evaluates whether the entity has alternative liquidity sources (undrawn facilities, asset disposals) to cover the gap.