The verdict in three sentences
A legacy Access or PHP application costs nothing while it works, then costs a great deal the day it stops, often after a Windows update, a retirement or a security breach. The right approach starts with a 3 to 5 day audit that decides between progressive migration and a full rewrite. Always plan 4 to 8 weeks of parallel running: it is the insurance that keeps you from losing a billing season.
Signals that demand action in 2026
In SMEs from Manchester to Ohio, the story repeats: an Access database built in 2009 by an enthusiastic employee, extended with VBA macros, shared on a file server, then turned into the core of quotes, stock or scheduling. On the web side, it is PHP 5 or PHP 7.0 code with no framework, out of security support for years.
| Signal | Concrete risk | 2-year likelihood (estimate) | Impact if it happens |
|---|---|---|---|
| The tool's creator has left or is retiring | Nobody can fix an error | High | Business area stopped for several days |
| Access file near the 2 GB limit | File corruption, slowness | Medium | Data lost since the last backup |
| PHP 5 or 7.0 without patches | Exploitable flaw, intrusion | High if internet-facing | Data breach, regulator notification within 72 h under UK GDPR |
| Multi-user access over a network share | Locks, write conflicts | High above 10 users | Re-keying, stock or billing errors |
| No mobile or remote access | Workarounds with Excel and email | Certain | Scattered data, decisions on wrong figures |
| Incompatible Office or server update | Macros or extensions stop working | Medium | Sudden lock-up, emergency call-out |
Progressive migration or rewrite: method and budgets
The audit inventories tables, queries, forms, macros and the business rules hidden in code. It also measures data quality: duplicates, free-text fields used as lists, inconsistent dates. In the UK market, such an audit costs, as a 2026 order of magnitude, 1,700 to 3,800 GBP (roughly 2,200 to 4,900 USD in the US).
| Approach | Principle | UK market cost (2026 order of magnitude) | Duration | When to choose it |
|---|---|---|---|---|
| Preliminary audit | Inventory, rule mapping, migration plan | 1,700 to 3,800 GBP | 3 to 5 days | Always |
| Stabilisation | Data moved to PostgreSQL or SQL Server, Access kept as front end | 7,000 to 13,000 GBP | 4 to 6 weeks | Emergency, tight budget |
| Progressive migration | Module-by-module rewrite as a web app, shared database | 21,000 to 51,000 GBP | 4 to 9 months | Critical tool, many users |
| Full rewrite | New web app, data migrated in one go | 30,000 to 77,000 GBP | 3 to 7 months | Simple rules or rules to rethink |
| Replace with a package | Configured off-the-shelf ERP or SaaS | 8,500 to 43,000 GBP + subscriptions | 2 to 6 months | Standard processes |
At Kolonell, a rewrite as a web application falls, depending on complexity, into the medium tier, 6,100 to 10,670 EUR, or the complex tier, 10,670 to 22,870+ EUR, delivered by a remote team with weekly reviews. The preliminary audit is quoted on request. Application maintenance is 53, 114 or 183 EUR a month depending on the level.
Data migration and parallel running
Data migration often accounts for 20 to 30 % of the effort. You must clean before migrating: a customer stored under 4 spellings becomes 4 customers in the new database. We run three migration rehearsals, the last on a Friday evening for a Monday cutover.
For 4 to 8 weeks, old and new tools run side by side. Users enter data in the new one, and a script compares key results (revenue, stock, receivables) with the old one. Final cutover only happens once differences have been zero for 2 consecutive weeks.
Mini case study
Mark, finance director of an electrical wholesaler in Birmingham (45 staff), relies on a 2009 Access database for quotes and order tracking. Twelve people use it. Each week the team loses about 9 hours to slowness, locks and re-keying into Excel: 9 × 46 weeks = 414 hours a year, about 14,500 GBP at 35 GBP an hour fully loaded.
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Then there is risk: a 5 working day outage would block about 50,000 GBP of quotes. With an estimated 25 % probability over 2 years, the average cost of inaction is close to 6,000 GBP a year on top of lost hours. A rewrite in Kolonell's complex tier, 10,670 to 22,870+ EUR, pays back in roughly 8 to 17 months from recovered hours alone.
FAQ
Can we keep Access during the migration?
Yes, it is even recommended: Access can act as a front end to a PostgreSQL or SQL Server database while modules are rewritten one by one. This stabilisation step usually takes 4 to 6 weeks.
How long does parallel running last?
Between 4 and 8 weeks depending on the number of processes and users. For a billing tool, we recommend covering at least one full month-end close in both systems.
Will business rules hidden in macros be lost?
No, the audit extracts and documents them one by one, usually 30 to 150 rules for a database of that generation. Each rule is validated with the business user before being rewritten.
Should we rewrite in modern PHP, Node.js or something else?
It depends on your teams and suppliers. We favour widely used technologies (TypeScript, PostgreSQL) so another provider can take over the code, and documentation ships with the source code.
What about data protection in the new application?
The rewrite is a chance to add access logs, role-based permissions and retention periods. Under UK and EU GDPR, a personal data breach must be reported within 72 hours, which is almost impossible with a tool that keeps no logs.
Let's scope your project. We start by auditing your Access database or PHP application to choose between progressive migration and rewrite, with a schedule that includes parallel running. 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.
