The verdict in three sentences
For a statutory audit firm (35 staff, 220 engagements, in London or Lyon), custom audit working papers software costs between EUR 45,000 and 80,000 excluding VAT in 2026, plus EUR 8,000 to 14,000 of annual maintenance. Market solutions charge EUR 1,200 to 2,500 per user per year, so EUR 42,000 to 87,500 a year for 35 users. Custom software pays back between year two and year three, provided it covers from day one general ledger imports, auditing standards checklists (ISAs (UK), or NEP in France) and statutory archiving, which decide the outcome of a regulator inspection.
The real cost of market tools
The engagement partner pays more than licences: re-keying, makeshift Excel exports and time spent adapting templates to the firm.
| Annual item (2026 order of magnitude) | Market solution | Custom software |
|---|---|---|
| Licences (35 users) | EUR 42,000 to 87,500 | EUR 0 |
| Maintenance and hosting | Included | EUR 8,000 to 14,000 |
| Re-keying trial balance, accounts, ledgers (220 engagements × 3 h) | 660 h, EUR 39,600 at EUR 60 hourly cost | 120 h, EUR 7,200 |
| Adapting templates and checklists | 80 h, EUR 4,800 | Built into development |
| Onboarding new staff | 2 days per joiner | 1 day per joiner |
| Estimated total annual cost | EUR 86,400 to 131,900 | EUR 15,200 to 21,200 |
Even at the low end, the annual gap exceeds EUR 70,000, covering the initial investment within 12 to 14 months.
Functional scope and budget
| Module | Scope | Indicative 2026 budget |
|---|---|---|
| Engagements and planning | Engagement letters, fees, partner rotation, hours budget | EUR 5,000 to 8,000 |
| Ledger and trial balance import | Standard audit file checks (FEC in France, SAF-T style exports), automatic trial balance | EUR 7,000 to 12,000 |
| Working papers by cycle | Lead schedules, cross-referencing, tests of detail | EUR 10,000 to 18,000 |
| Standards checklists | ISA 200 to 700 (or NEP), report, representation letter, risk assessment | EUR 6,000 to 10,000 |
| Tiered review | Staff, manager, partner, EQCR, blocking review notes | EUR 6,000 to 11,000 |
| Statutory archiving and audit trail | File close, timestamping, 6-year retention, locking | EUR 5,000 to 9,000 |
| Dashboards | Engagement progress, hours, deadline alerts | EUR 3,000 to 6,000 |
| Data migration and training | Existing templates, 2 years of files | EUR 3,000 to 6,000 |
Delivery takes 5 to 8 months. Go-live should avoid the 31 December busy season: launching in June or July leaves time to test on non-calendar year-end engagements.
Compliance requirements not to overlook
During an inspection (FRC or ICAEW in the UK, H3C in France), the software must show that every procedure was performed, reviewed and documented before the report was signed. In practice: a tamper-proof audit trail (who changed what, when), file lock within 60 days of signing, at least 6 years of retention, and hosting compliant with GDPR and professional confidentiality (UK or EU hosting, encryption at rest). Ledger imports must check mandatory fields and flag anomalies (unbalanced entries, dates outside the period) before the team starts work.
Mini case study
Mr Girard, engagement partner in a 35-person firm, pays EUR 1,800 per user per year, so EUR 63,000 in licences, and his teams spend about 660 hours a year re-keying (EUR 39,600). He invests EUR 68,000 in custom software, with EUR 11,000 of annual maintenance and hosting. 120 hours of residual re-keying remain (EUR 7,200). Annual saving: 63,000 + 39,600 − 11,000 − 7,200 = EUR 84,400. Payback: about 10 months, and the 540 freed hours can go to billable work.
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FAQ
Will custom software pass a regulator inspection?
Yes, inspectors review the quality and documentation of procedures, not the software brand. Audit trail, tracked review and a file locked within 60 days are what they examine.
Does the firm own the code?
That is negotiated in the contract: an assignment of economic rights is common and adds 0 to 10% to the price. The firm then remains free to change supplier.
What does secure hosting cost?
Allow EUR 300 to 700 a month for certified hosting (ISO 27001), backups included.
Can prior-year files be migrated?
Yes, at least the last two years to keep lead schedules continuous. Allow EUR 3,000 to 6,000 depending on the current tool's export format.
From what size does custom software make sense?
Below 15 users, market licences (under EUR 37,500 a year) are often cheaper. Above 25 users, custom software pays back in under 2 years.
Let's scope your project. Send us your headcount, engagement count and current tools: we will price working papers software between EUR 45,000 and 80,000, delivered in 5 to 8 months outside busy season. 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.
