The verdict in three sentences
Automating dunning for overdue invoices costs 6,000 to 20,000 EUR in 2026 and deploys in 4 to 8 weeks. The impact is immediate: -30 % DSO on average, meaning cash freed without borrowing. It is one of the rare automation projects whose ROI falls under 6 months, because it acts directly on cash.
The dunning scenarios that work
Effective dunning is not a single reminder, it is a graduated cadence that raises pressure without breaking the client relationship. Automation applies that cadence with no lapses or delays.
| Step | Trigger | Channel | Tone |
|---|---|---|---|
| Pre-due | 3 days before due | Courteous, informative | |
| Reminder 1 | 3 days overdue | Factual reminder | |
| Reminder 2 | 10 days overdue | Email + SMS | Firm, deadline |
| Reminder 3 | 20 days overdue | SMS + scheduled call | Pre-litigation |
| Formal notice | 30 days overdue | Letter / registered | Formal |
| Escalation | 45 days overdue | Credit manager alert | Human decision |
The key is not sending more reminders, but sending them at the right time, on the right channel, with no manual work and a full audit trail.
The quantified impact on DSO and cash
DSO (Days Sales Outstanding) measures the average collection time. Every day saved is cash arriving sooner. Here is the typical effect of automation in 2026.
| Indicator | Before automation | After | Gain |
|---|---|---|---|
| Average DSO | 58 days | 40 days | -18 days (-31 %) |
| Invoices chased on time | 55 % | 98 % | +43 pts |
| Accounting time / week | 5 h | 1 h | -4 h |
| Overdue > 60 days | 12 % | 5 % | -7 pts |
| Cash freed (3M EUR revenue) | — | ≈ 148,000 EUR | one-off |
On 3M EUR of revenue, cutting DSO by 18 days permanently frees roughly 148,000 EUR of cash. That figure is what makes the project obvious.
Mini case study
Sophie, credit manager at a 60-employee services SME (3.2M EUR revenue), suffers a 56-day DSO and spends 5 hours/week chasing manually. She deploys a workflow connected to her billing for 12,000 EUR. Three months later, her DSO drops to 39 days (-17 days), freeing ≈ 149,000 EUR of cash and 4 hours/week. The project pays for itself in under 4 months on time saved alone, the cash gain being pure bonus.
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FAQ
Will automation alienate my clients?
No, quite the opposite: graduated, courteous scenarios professionalise dunning. The tone rises progressively and litigation escalation always remains a human decision.
Does it connect to my billing tool?
Yes, most software (Sage, Pennylane, QuickBooks, ERP) exposes an API or export. The workflow reads due invoices and triggers reminders automatically.
What DSO gain can I expect?
On average -30 %, or 15 to 20 days for a starting DSO around 55-60 days. The gain depends on your current discipline: the more irregular your reminders today, the bigger the impact.
How long to deploy?
Between 4 and 8 weeks depending on the number of scenarios and channels (email, SMS, letter). An email-only scope deploys faster than a full multichannel setup.
Is ROI really under 6 months?
Yes, in most cases, because the project acts on two levers: accounting time saved and cash freed. On multi-million revenue, cash alone amply repays the investment.
Let's scope your project. Send us your current DSO, revenue and billing tool, and we will quantify the cash freed and the budget (6,000 to 20,000 EUR). Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
