The verdict in three sentences
For a 70-person SME in London, automating invoice reminders costs between 6,000 and 18,000 EUR excluding VAT (roughly 5,100 to 15,300 GBP), accounting integration included. With 68 days of DSO and 210,000 EUR overdue, bringing DSO down to 48 days frees up about 600,000 EUR of cash, which pays back the project within weeks. The decisive lever is customer segmentation and a daily sync with Xero, Sage or your ERP, far more than simply sending emails.
What an automated reminder process really covers
A serious dunning tool reads open invoices from your accounting software every morning, applies a scenario based on the customer profile, and only escalates to the finance team the cases that need a human. Incoming payments stop the sequence automatically, so you never chase a customer who has already paid.
| Project level | Scope | 2026 budget (EUR excl. VAT) | Timeline |
|---|---|---|---|
| Configured SaaS tool | Standard scenarios, email templates, native connector | 6,000 to 8,000 + 150 to 400 EUR/month | 3 weeks |
| SaaS + advanced integration | Customer segments, SMS reminders, dispute export, CRM link | 9,000 to 13,000 | 5 weeks |
| Custom module | Your own business rules, customer payment portal, escalation workflows | 14,000 to 18,000 | 7 to 8 weeks |
| Online payment option | Card or instant bank transfer link in every reminder | 1,500 to 3,000 | 1 week |
| Training and change management | Workshops for finance and sales teams | 800 to 1,500 | 2 days |
| Annual maintenance | API updates, scenario tuning | 10 to 15% of build | Ongoing |
These 2026 estimates reflect day rates charged by independent integrators and agencies, between 550 and 750 EUR per day (London rates often sit at the upper end).
Reminder scenarios by customer segment
You do not chase a large industrial account the way you chase a tradesman. Segmentation is what brings DSO down without damaging the commercial relationship.
| Segment | Share of receivables | Recommended scenario | Expected effect on payment time |
|---|---|---|---|
| Key accounts (over 50,000 EUR/year) | 45% | D-5 polite reminder, D+7 email to accounts payable, D+15 call from the CFO | -12 days |
| Regular SMEs | 30% | D-3 reminder, D+5, D+15, D+30 formal notice | -22 days |
| Small and one-off customers | 15% | D+1, D+8 SMS, D+20 payment link, D+35 handover to collections | -25 days |
| Public sector customers | 7% | Verified e-invoice submission, D+30 reminder | -8 days |
| Disputed accounts | 3% | Sequence paused, alert to the account manager | Dispute settled in 10 days instead of 40 |
Regulatory reminder: in the UK, the Late Payment of Commercial Debts Act lets you claim statutory interest at 8% above the Bank of England base rate plus fixed compensation of 40 to 100 GBP per invoice, which can be mentioned in later reminders.
Xero, Sage or your ERP: the integration makes the project
Sync quality drives everything. Xero, Sage Intacct and Sage 50 expose usable APIs; an on-premise Sage install sometimes needs a middleware connector, adding 2,000 to 4,000 EUR. Plan for at least a daily sync of invoices, credit notes and payments, and keep bank reconciliation current, otherwise the tool will chase invoices that are already paid.
Mini case study
Claire, CFO of a 70-person industrial SME in East London, runs 11 million EUR in revenue. Her DSO is 68 days. She picks the SaaS option with advanced Xero integration: 11,500 EUR set-up and 290 EUR per month.
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
- Cash gain: 20 fewer days of DSO x 11,000,000 / 365 = about 603,000 EUR of revenue collected earlier, reducing working capital needs by the same amount.
- Financing cost avoided at 5.5% on that 603,000 EUR: about 33,000 EUR per year.
- Time freed: 1.5 days per week of an accountant costing 42,000 EUR fully loaded, i.e. about 12,600 EUR per year reallocated to analysis.
- First-year cost: 11,500 + 3,480 = 14,980 EUR, covered in under four months by financing and time savings alone (45,600 EUR per year).
FAQ
How much does reminder automation cost for a 70-person SME?
Budget 6,000 to 18,000 EUR excluding VAT in 2026 depending on integration depth, plus 150 to 400 EUR per month if you start from a SaaS. The accounting integration often accounts for 30% of the budget.
What DSO improvement can we expect?
For a B2B SME currently chasing by hand, a 15 to 25 day gain is a common 2026 order of magnitude. Going from 68 to 48 days within six months is realistic.
Will automated reminders annoy our customers?
Not if scenarios are segmented and stop as soon as payment arrives. Key accounts get a short, polite sequence, and 100% of reminders are personalised with the contact name and purchase order number.
Do we need to change accounting software?
No. Xero, Sage, QuickBooks and most market tools connect. Only software without an API requires a scheduled export, adding 2,000 to 4,000 EUR.
How long until it is live?
From 3 weeks for a configured SaaS to 8 weeks for a custom module, testing included. The first effects on overdue balances show up in month two.
Let's scope your project. Send us your invoice volume, accounting software and current DSO: we will price a scope between 6,000 and 18,000 EUR with a go-live date. 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.
