The verdict in three sentences
A 15-year-old Access database, maintained by an employee who has since left, is a dated operational risk: the question is no longer whether it will break, but when. In 2026, replacing Access and its satellite Excel files with a custom web application costs roughly GBP 13,000 to 35,000 in London, data migration included, for a 6 to 12 week project. A single three-day outage on invoicing or stock often costs more than the migration itself.
What the migration costs in 2026
The ranges below are 2026 orders of magnitude seen at London agencies and IT consultancies for an SME with 50 to 150 staff. Price depends mainly on the number of screens, the business rules hidden in VBA macros and the quality of the data to migrate.
| Scope | Screens / forms | Business rules (VBA, queries) | Budget (ex VAT) | Timeline |
|---|---|---|---|---|
| Simple database (1 department) | 8 - 12 | 10 - 20 | GBP 13,000 - 17,000 | 6 - 7 weeks |
| Intermediate database | 15 - 25 | 30 - 60 | GBP 17,000 - 26,000 | 8 - 10 weeks |
| Critical multi-department database | 30 - 45 | 60 - 120 | GBP 26,000 - 35,000 | 10 - 12 weeks |
| Data migration (included) | - | Cleaning, deduplication | 10 - 15 % of budget | 1 - 2 weeks |
| Hosting + backups | - | - | GBP 35 - 100/month | - |
| Ongoing maintenance | - | - | GBP 250 - 800/month | - |
For comparison, Kolonell prices a business application on its own grid: 2,500,000 - 4,000,000 FCFA (EUR 3,810 - 6,100) for a simple app, 4,000,000 - 7,000,000 FCFA (EUR 6,100 - 10,670) for medium complexity and 7,000,000 - 15,000,000+ FCFA (EUR 10,670 - 22,870+) for a complex tool, with maintenance at 35,000, 75,000 or 120,000 FCFA per month (EUR 50, 110 or 180).
The risks to quantify before deciding
The real cost of an Access database never shows up in the IT budget: it hides in re-keying hours, Excel files copied onto USB sticks and dependency on a single person.
| Risk | Access + Excel today | Web application | Estimated impact |
|---|---|---|---|
| .accdb file outage or corruption | Common above 2 GB or 10 users | PostgreSQL database backed up nightly | 2 - 5 days down, GBP 7,000 - 22,000 |
| The person who "knows" leaves | No documentation | Versioned code, documentation delivered | 3 - 6 weeks to rebuild knowledge |
| Remote access | Slow VPN, Office licences | Browser, mobile | 30 - 60 min lost per day per field user |
| Re-keying between Excel and Access | 5 - 15 h per week | Single data entry | 250 - 750 h per year |
| UK GDPR and audit trail | No access log | Roles, change history | Exposure during an ICO inquiry |
| End of Office / Windows support | Uncertain compatibility | Device-independent | Forced emergency migration |
The scenario to avoid: migrating in a rush after an outage, with no specification, paying 30 to 50 % more for half the timeline.
The method that limits nasty surprises
A successful migration starts with a 3 to 5 day audit (GBP 1,300 to 3,000): an inventory of tables, queries, macros and the Excel files feeding the database. You almost always discover 20 to 40 % of undocumented business rules. Then come screen mock-ups with users, development in batches, and a 2 to 4 week parallel run during which Access stays available read-only.
Mini case study
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Mark, head of administration at an 80-employee manufacturing SME on the outskirts of London, runs orders, stock and invoicing on a 1.6 GB Access database built in 2011. He counts 10 h of re-keying per week at GBP 33 loaded cost per hour, i.e. GBP 16,500 per year over 50 weeks. The last file corruption blocked invoicing for 3 days, roughly GBP 10,500 in delayed cash collection and lost hours. A quote of GBP 23,000 plus GBP 520 monthly maintenance gives a first-year cost of GBP 29,240, against GBP 27,000 in avoided losses: the migration pays back in about 13 months, before even counting the key-person risk.
FAQ
Can we keep Access running until the application is ready?
Yes, it is recommended: Access stays in production during development, then read-only for a 2 to 4 week parallel run. The final cutover happens over a weekend, with the data migration rehearsed at least 2 times beforehand.
How long does the data migration take?
Allow 1 to 2 weeks for a database of 50,000 to 500,000 rows, cleaning and deduplication included. This item usually accounts for 10 to 15 % of the total budget.
Should we use Power Apps instead of custom development?
Power Apps works for 5 to 10 simple screens, but licences cost around GBP 17 per user per month, i.e. GBP 16,300 per year for 80 staff. Beyond 30 business rules, a custom web app is often cheaper over 3 years.
Will users have to relearn everything?
A good migration keeps the logic of existing screens and simplifies the rest: half a day of training per department is enough in 80 % of cases. Screens are validated as mock-ups before development.
What if the VBA macros are impossible to understand?
The audit replays them with real data to rebuild the rules, which takes 1 to 3 days depending on volume. That is exactly why the audit must come before any firm quote.
Let's scope your project. Send us the list of your Access tables and Excel files: we will price the audit, the web application scope and the cutover timeline. 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.
