The verdict in three sentences
To run assignments, time spent and margins, a consulting firm chooses between an ERP SaaS at 30-90 EUR/user/month and a custom tool at 30,000-70,000 EUR. The ERP wins when your processes are standard and your headcount modest; custom wins when per-assignment profitability tracking and staffing are your core business. The tipping point sits around 15-20 consultants and is confirmed by five-year TCO.
ERP SaaS or custom: the business comparison
A professional services ERP (PSA) covers the standard quickly; custom fits your margin and staffing rules.
| Criterion | ERP SaaS (PSA) | Custom |
|---|---|---|
| Upfront cost | 3,000 - 12,000 EUR (setup) | 30,000 - 70,000 EUR |
| Recurring cost | 30 - 90 EUR/user/month | Hosting + maintenance 10-15%/yr |
| Per-assignment profitability | Standard | Custom, fine-grained |
| Staffing & capacity plan | Often basic | Fits your rules |
| Time to go live | 4 - 10 weeks | 12 - 20 weeks |
| Business fit | Medium | Total |
| Code ownership | Vendor | You |
An ERP quickly covers time-tracking and billing; custom becomes relevant when the granularity of margin calculation per consultant and per assignment is part of your competitive edge.
5-year TCO: the tipping point
The real criterion is total cost of ownership. Here is an estimate, a 2026 order of magnitude, for different headcounts.
| Headcount | ERP SaaS at 60 EUR/user/month over 5 yrs | Custom 50,000 EUR + maintenance 12%/yr |
|---|---|---|
| 10 consultants | 36,000 EUR | 80,000 EUR |
| 20 consultants | 72,000 EUR | 80,000 EUR |
| 30 consultants | 108,000 EUR | 80,000 EUR |
| 50 consultants | 180,000 EUR | 80,000 EUR |
| 80 consultants | 288,000 EUR | 80,000 EUR |
At 20 consultants, both options converge around 72,000-80,000 EUR over five years. Below that, ERP SaaS stays cheaper; above it, custom widens the gap because it does not cost per seat. At 50 consultants, the gap exceeds 100,000 EUR in favour of custom.
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Mini case study
Claire is a partner at a consulting firm in Lyon: 34 consultants, an ERP SaaS at 65 EUR/user/month, i.e. 26,500 EUR/year and 132,500 EUR over five years. The ERP does not calculate per-assignment margin at the desired level of detail, hiding loss-making assignments. She invests 58,000 EUR in a custom tool: over five years, maintenance included, TCO drops to about 93,000 EUR, saving 40,000 EUR. Above all, spotting low-margin assignments lets her readjust her rates and gain several profitability points.
FAQ
From how many consultants does custom become profitable? Around 15-20 consultants over a five-year horizon. Below that, a SaaS ERP is generally cheaper.
What is custom's main advantage for a firm? Business fit: fine per-assignment profitability tracking, staffing to your rules and custom reporting. That is what earns margin points.
How long to deploy each option? A SaaS ERP goes live in 4 to 10 weeks; a custom tool needs 12 to 20 weeks depending on scope.
Can we start with an ERP then migrate? Yes, a common path: start on SaaS, then move to custom when headcount and granularity needs justify the investment.
Does custom include time-tracking and billing? Yes: time entry, capacity plan, billing and margin tracking are in the core at 30,000-70,000 EUR.
Let's scope your project. Tell us your number of consultants, your current tool and your profitability tracking needs, your indicative budget and target timeline, and we will frame the decision. 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.
