The verdict in three sentences
Migrating data from a legacy ERP to a new platform costs between €10,000 and €40,000 in 2026, depending on volume, source data quality and the number of entities. The risk isn't technical but operational: a failed cutover halts invoicing, orders or payroll. A controlled migration relies on a tested ETL, rigorous cleansing and a cutover plan with rollback, targeting under 0.1% error.
Migration stages and their risks
A migration isn't a simple copy. Each stage carries a specific risk to anticipate and test.
| Stage | Deliverable | Main risk |
|---|---|---|
| Source data audit | Mapping, quality | Undetected inconsistencies |
| Cleansing and deduplication | Sanitized data set | History loss |
| Old → new model mapping | Correspondence table | Misaligned fields |
| ETL development | Extract/transform scripts | Underestimated volume |
| Regression testing | Acceptance report | Gaps unseen before cutover |
| Cutover + rollback | Documented procedure | Prolonged downtime |
Cleansing is often the heaviest item: in a 10-year-old ERP, 5 to 15% of records have duplicates, empty fields or inconsistent formats that must be arbitrated with the business.
2026 budget breakdown
Price depends mostly on volume, the number of entities (customers, products, invoices, stock) and the gap between old and new models.
| Item | Range | Note |
|---|---|---|
| Data audit and mapping | €1,500 – 5,000 | Quality, volume |
| Cleansing and deduplication | €2,000 – 8,000 | Depending on data state |
| Mapping and transformation rules | €2,500 – 8,000 | Core of the complexity |
| ETL development and execution | €3,000 – 12,000 | Iterative loading |
| Regression testing | €2,000 – 6,000 | Automated checks |
| Cutover rehearsals | €1,500 – 5,000 | De-risk go-live |
Cutover rehearsals (at least two dry runs) are the project's life insurance: they measure the real migration duration, validate rollback and avoid nasty surprises on go-live weekend.
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Mini case study
Nadia, IT director of a 150-person distributor in Toronto, replaces a 12-year-old ERP. Volume: 180,000 customers, 420,000 invoices, 35,000 product SKUs. The migration project is quoted at €26,000, including €7,000 of cleansing (12% of records to fix). After two dry runs, the real cutover takes 6 hours on a Sunday, with a measured error rate of 0.04% (72 anomalous records, fixed on D+1). Cost of a failed cutover avoided: a day of halted invoicing represented about €35,000 of unissued revenue, before counting lost team confidence. The investment pays for itself on go-live security alone.
FAQ
Big bang or phased migration? Big bang (all in one cutover) suits coherent, tested scopes; phased migration (by entity or site) reduces risk but forces temporary coexistence of both systems. The choice depends on your tolerance for downtime.
How do you guarantee no data is lost? Through automated reconciliation checks: counts, checksums, sampling. Each source table must be reconciled with its target, targeting under 0.1% variance, with every gap traced and fixed.
Should you migrate everything or archive part? Rarely everything: old history (beyond legal obligations) can be archived off-platform, lightening both the migration and the new database. Define a clear active scope with the business and legal.
How long does a migration take? Expect 6 to 12 weeks: 1 to 2 audit, 2 to 3 cleansing and mapping, 2 to 4 ETL development and testing, plus cutover rehearsals. The cutover itself takes from a few hours to a weekend.
What if the cutover fails? A documented, tested rollback plan: return to the old system within a bounded time (often under 2 hours), with clear go/no-go decision criteria validated in rehearsal. Without reliable rollback, don't start the cutover.
Let's scope your project. Tell us your source ERP, the data volume (customers, invoices, products) and your cutover window: we'll frame the approach, an indicative budget of €10,000 to €40,000 and a 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.
