The verdict in three sentences
A custom practice management platform for an accounting firm costs 35,000 to 90,000 EUR, versus 30 to 80 EUR per staff member per month for a market SaaS license. Custom pays off once you exceed 12 to 15 staff and the cost of data-entry friction outweighs the build's amortization. In practice, the real gain is recovered billable time: 8 to 15 hours per week per team, reinvested into production.
Custom vs license: the real math
SaaS is unbeatable at the start: no upfront investment, live in days. But cost scales linearly with headcount, and you bend your processes to the tool — not the reverse. Custom flips the logic: high upfront cost, then a near-zero marginal cost per new hire.
| Criterion | Custom | SaaS license |
|---|---|---|
| Upfront cost | 35,000 - 90,000 EUR | 0 EUR |
| Monthly cost (20 staff) | ~1,000 EUR (maintenance) | 600 - 1,600 EUR |
| Time to go live | 14 - 22 weeks | 1 - 4 weeks |
| Fit to your processes | Total | Limited |
| Accounting production integration | Native, custom | Standard connectors |
| Code ownership | The firm | The vendor |
| 5-year cost (20 staff) | ~110,000 EUR | 108,000 - 216,000 EUR |
What the functional scope covers
A firm doesn't just manage files — it manages profitability per engagement. The 2026 baseline combines client relationship management, time entry, tax and social deadlines, and time-linked billing.
| Module | Main gain | Dev effort (order of magnitude) |
|---|---|---|
| Client file management | 360° client view | 3 - 4 weeks |
| Time entry and tracking | Basis for billing | 3 - 5 weeks |
| Tax / social deadline tracker | Zero missed deadlines | 2 - 3 weeks |
| Automated billing | Collection time -20% | 3 - 4 weeks |
| Profitability dashboard | Margin visible per engagement | 2 - 3 weeks |
| Production integration (API) | End of double entry | 3 - 6 weeks |
| Document management + client portal | Files in the right place | 3 - 4 weeks |
Budget an annual maintenance of 15% of the build cost for corrective and evolutionary work plus yearly compliance updates.
Mini case study
Claire runs a 22-person accounting firm in Nantes. Her teams lose on average 10 hours per week per department to double entry between the production tool and tracking spreadsheets. Across 4 departments that's 40 hours weekly — at a loaded cost of roughly 45 EUR/h, about 1,800 EUR wasted per week, or nearly 86,000 EUR per year.
She commissions a custom tool at 62,000 EUR, with maintenance of 9,300 EUR/year. Recovering even 60% of the lost time saves ~52,000 EUR in year one. The investment is amortized in about 20 months, and recovered time is partly re-billed to clients — accelerating ROI further.
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FAQ
How much does accounting practice management software really cost in 2026?
Custom runs 35,000 to 90,000 EUR depending on modules and integrations. A SaaS license is 30-80 EUR per staff member per month, or 7,200 to 19,200 EUR per year for 20 people.
What is the implementation timeline?
A custom project takes 14 to 22 weeks depending on scope. A license deploys in 1 to 4 weeks, but configuration and data migration must be planned in both cases.
Can it connect to my existing accounting production tool?
Yes. Most production tools expose APIs or exports. Custom integration eliminates double entry — the main time sink — for a dev effort of 3 to 6 weeks.
At what size does custom become worthwhile?
Generally beyond 12 to 15 staff, or as soon as a specific process that SaaS can't cover costs more than amortizing the build over 3 to 5 years.
Do I need a maintenance budget?
Yes. Annual maintenance of about 15% of the build cost covers fixes, upgrades and compliance. On a 62,000 EUR build, that's about 9,300 EUR per year.
Let's scope your project. Tell us your headcount, current production tool and critical processes, and we'll frame the scope and an indicative budget. 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.
