The verdict in three sentences
In a business software replacement, it is not the software that sinks the project, it is the data migration. In 2026, in Dublin, it accounts for 15 to 30 % of the budget and, poorly prepared, delays go-live by 1 to 3 months. The safeguard: a staging environment, transitional dual entry and a validated rollback plan before cutover.
The data migration cost items
Migrating is not copying: it is extract, cleanse, transform, load and check. Each stage has its own cost and risk.
| Stage | Share of migration budget | Risk if neglected |
|---|---|---|
| Source extraction | 10 - 15 % | Incomplete data |
| Cleansing / de-duplication | 25 - 35 % | Duplicates in production |
| Field mapping | 20 - 30 % | Misplaced data |
| Loading (ETL) | 15 - 20 % | Mass rejections |
| Checks / acceptance | 15 - 25 % | Errors found too late |
Cleansing is almost always underestimated: poor-quality source data can double this item.
The total replacement cost in 2026
Beyond migration, budget the whole replacement. Here is a 2026 ballpark for a mid-sized project.
| Item | 2026 ballpark (EUR) | Comment |
|---|---|---|
| Software / development | 40,000 - 100,000 | Vertical or custom |
| Data migration | 8,000 - 45,000 | 15-30 % of project |
| Integrations | 6,000 - 30,000 | ERP, accounting, payroll |
| User training | 3,000 - 10,000 | Key to adoption |
| Change management | 4,000 - 15,000 | Reduces rejection |
| Total replacement | 50,000 - 150,000 | Scope-dependent |
Source data quality is the number-one factor pushing a project from the bottom to the top of the range.
Securing cutover: the three safety nets
Three measures prevent disaster on D-day. The staging environment replays the migration on real data before production. Transitional dual entry (old + new for 2-4 weeks) ensures continuity if a problem arises. The documented rollback plan allows a return to the old system in hours, not days. Without these nets, a failed migration can paralyze billing or inventory.
Mini case study
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Peter, CFO of a trading SME in Dublin (EUR 22M turnover), replaces a 14-year-old management system. His project is estimated at EUR 95,000. A quick audit reveals 18 % of his customer base contains duplicates and missing fields. By budgeting EUR 22,000 for migration (23 % of the project) with serious cleansing, he avoids a 2-month go-live delay. That delay would have cost, in dual operation and lost hours, around EUR 30,000. The extra migration investment produced a net gain of EUR 8,000 and a clean start.
FAQ
Why is data migration so expensive?
Because 60 to 80 % of the effort is cleansing and mapping, not simple copying. Heterogeneous source data spanning several years demands manual reliability work.
Can you migrate without losing history?
Yes, but you must arbitrate: importing everything is costly and pollutes the new system. Best practice is to import active data (customers, stock, open items) and archive the rest read-only.
How long does a migration take?
From 1 to 4 months depending on volume and data quality. The acceptance and checking phase often represents a third of total time.
What is a rollback plan?
A documented procedure to return to the old system if cutover fails. It turns a critical incident into a simple few-hour reversal.
Should you keep the old software after cutover?
Yes, read-only for a few months, until you confirm all data is usable. It is cheap insurance against nasty surprises.
Let's scope your project. Tell us your current software, the volume of data to migrate and your cutover deadline, and we will price a secured migration with a rollback 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.
