What Is Your Real Collection Period (DSO) Per Customer?
Term 5 Oct 2026 DSOcash flowaccounts receivablepayment termsCRM metrics
Your real collection period is the median number of days between issuing an invoice and the money actually landing in your account — calculated per customer, not for the business as a whole. The gap between that figure and the contractual term written into the agreement tells you whether the payment terms you grant are realistic or simply wishful thinking.
Why It Matters
A single company-wide average gives false comfort: thirty days on average might mean two customers paying within ten days and a third paying after ninety. The average conceals precisely the customer draining your liquidity.
For a manager, the metric has three immediate uses: setting renewal payment terms based on documented payment behaviour rather than impressions; pricing the time cost of money into the quote instead of letting it quietly erode the margin; and structuring sales commission so a deal isn't treated as closed until the cash is collected.
How to Calculate It
For each customer, take the last twelve months of invoices:
| Element | Detail |
|---|---|
| Start date | Invoice issue date, not the order date |
| End date | Date funds clear, not the transfer date |
| Calculation | Sum the day differences, divide by invoice count |
| Variance | Actual period minus contractual term |
Then sort customers into three tiers: disciplined (variance under five days), habitually late, and delinquent. Attach a written policy to each tier: the first earns extended terms, the second requires a deposit, the third pays before delivery.
The rule: no customer gets better payment terms than their behaviour has proven they deserve.
A Worked Example
Imagine a building materials supplier that grants all customers sixty-day terms. Calculating the collection period per customer revealed that one contractor paid after an average of 105 days, while three others paid within forty. The decision wasn't to cut the contractor off — it was to move him to a 40% upfront deposit, and to offer the other three an early-payment discount funded by the savings that change generated.