The verdict in three sentences
For a 25-lawyer corporate firm in London, an off-the-shelf platform like Clio remains the fastest choice if your fee arrangements are standard (hourly rates, simple fixed fees). A custom build at 50,000-110,000 EUR pays back in around 36 months once you bill fixed fees per phase, success fees or client-level caps that packaged software handles poorly. The real decision rests on your unbilled time rate: each point recovered is worth roughly 45,000 EUR a year for a firm of this size.
What each option costs over five years
Practice management licences range in 2026 from 60 to 120 EUR (about 50 to 100 GBP) per user per month depending on modules (time, billing, document management, accounting, calendar). For 25 lawyers and 8 support staff, the maths is quick.
| Item (2026 estimate) | Off-the-shelf (Clio type) | Kolonell custom build |
|---|---|---|
| Annual licences (33 users) | 23,800 to 47,500 EUR | 0 EUR |
| Setup and data migration | 6,000 to 15,000 EUR | Included in project |
| Initial development | 0 EUR | 50,000 to 110,000 EUR |
| UK or EU sovereign hosting | Included | 4,800 to 9,600 EUR per year |
| Ongoing maintenance | Included (no roadmap control) | 9,000 to 16,000 EUR per year |
| Five-year cumulative cost | 125,000 to 252,500 EUR | 119,000 to 238,000 EUR |
| Break-even point | Immediate | 30 to 40 months |
Custom software does not win on raw cost. It wins when it recovers billable time that packaged software lets slip, and when the firm wants to own its tool and its data.
What a custom build covers better than packaged software
A London corporate firm rarely has a single fee logic. It mixes partner hourly rates, fixed fees per deal phase, retainer subscriptions and success fees. Packaged tools handle these through workarounds, which pushes associates to keep a spreadsheet on the side.
| Business need | Off-the-shelf software | Custom development |
|---|---|---|
| Time entry per matter and phase | Yes, generic phases | Phases mapped to your engagement letters |
| Capped fixed fee with 80 % alert | Partial | Yes, email alert and dashboard |
| Conditional success fee | Manual entry | Automatic calculation at closing |
| Court e-filing and SRA reporting | Yes | Yes, via dedicated connector |
| UK or EU hosting, encryption at rest | Depends on vendor | Contractual, your choice of host |
| Conflict checks | Basic | Search across parties, groups and directors |
| Accounting export to your auditor | Standard formats | Your accountant's exact format |
Legal professional privilege requires an audit trail of access. A custom build allows per-matter access logs, strict ethical walls on sensitive matters and full data portability, three points to check in any vendor contract.
Mini case study
James, managing partner of a 25-lawyer firm in the City, estimates that 6 % of hours worked are never billed: late time entries, fixed fees exceeded without alerts, forgotten disbursements. Annual revenue is 7.5 million EUR.
- Current unbilled time: 6 % of 7.5 M EUR, i.e. 450,000 EUR.
- Realistic target with mobile time entry, daily reminders and cap alerts: bring this rate down to 4.5 %.
- Annual gain: 1.5 points, i.e. 112,500 EUR.
- Custom investment: 85,000 EUR plus 20,000 EUR a year for hosting and maintenance.
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Even counting only half the estimated gain, 56,000 EUR a year, the project pays back in under two years, before counting the 30,000 EUR of licences saved each year.
FAQ
How long does it take to build custom practice management software?
Allow 4 to 7 months for a first version covering time, billing, matters and conflict checks. A phased rollout puts time entry in users' hands from month 3.
Can we migrate our history from Clio or another platform?
Yes, migration usually covers 5 to 10 years of matters, clients and invoices. Budget 8,000 to 15,000 EUR depending on the quality of available exports.
Where is privileged data hosted?
With a UK or EU host, with encryption at rest and in transit and daily backups kept for 30 days. The budget sits between 400 and 800 EUR a month.
Is custom software relevant for a 5-lawyer firm?
Rarely. Below 12 to 15 lawyers, licences stay under 15,000 EUR a year and well-configured packaged software is enough in most cases.
Who owns the source code at the end of the project?
The firm, if the contract assigns the intellectual property rights. That is our default practice, with technical documentation and full repository access.
Let's scope your project. Send us your standard engagement terms and user count: we will price a realistic scope between 50,000 and 110,000 EUR with a 4 to 7 month plan. 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.
