The verdict in three sentences
Migrating a legacy app to the cloud costs, in 2026, between 10,000 EUR (excl. VAT) (a simple "lift and shift" rehost) and 150,000 EUR (excl. VAT) (a microservices refactor), with a 3- to 9-month timeline depending on strategy. The return on investment shows up as up to -30 % in operating costs, regained scalability and compliant security. The key: pick the right strategy among the 5 Rs rather than rewriting everything by reflex.
The 5 migration strategies (the 5 Rs)
Not all migrations are equal. The "5 Rs" model helps arbitrate between speed, cost and long-term benefit.
| Strategy | 2026 indicative cost (EUR excl. VAT) | Timeline | Operating gain |
|---|---|---|---|
| Rehost (lift & shift) | 10,000 - 40,000 | 1-3 months | -10 to -15 % |
| Replatform (adjustments) | 25,000 - 70,000 | 2-5 months | -15 to -25 % |
| Refactor (cloud-native rewrite) | 40,000 - 150,000 | 4-9 months | -25 to -30 % |
| Repurchase (switch to SaaS) | Subscription | 1-4 months | Variable |
| Retire (decommission) | 2,000 - 8,000 | 1 month | 100 % of legacy |
Rehost is fastest but carries technical debt into the cloud. Refactor costs more but unlocks scalability and durably cuts the bill. In 2026, a hybrid approach (rehost first, gradual refactor) limits risk.
Total cost and savings over 3 years
The real trade-off shows over time. Here is a typical projection for a mid-sized business app in 2026.
| Item | Legacy on-premise | After cloud migration |
|---|---|---|
| Servers & hardware | 12,000 EUR/year | 0 (cloud-included) |
| Cloud hosting | 0 | 6,000 - 18,000 EUR/year |
| Infra maintenance | 8,000 EUR/year | 3,000 EUR/year |
| Incidents / downtime | 6,000 EUR/year | 2,000 EUR/year |
| Migration cost (one-off) | 0 | 40,000 EUR |
| 3-year total | 78,000 EUR | ~73,000 EUR |
From year 4, the migrated app costs markedly less, while offering security, automatic backups and elasticity. These are 2026 order-of-magnitude figures, to refine by volume and criticality.
Mini case study
Mehdi, CIO of a distribution group in Bordeaux, runs a stock-management app on a physical server from 2014. Average downtime: 2 days/year at 4,000 EUR/day of lost revenue. He chooses a replatform at 55,000 EUR (excl. VAT) over 4 months. Result: Scaleway hosting 9,000 EUR/year vs 20,000 EUR/year of on-premise infra, i.e. 11,000 EUR saved per year, plus the end of server outages (8,000 EUR/year avoided). ROI reached in about 2.9 years, with security and GDPR compliance finally under control.
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FAQ
How much does a legacy-to-cloud migration cost in 2026?
From 10,000 EUR for a simple rehost to 150,000 EUR for a full cloud-native refactor. Cost depends on code volume, obsolete dependencies and the level of rewrite desired.
How long does a migration take?
Between 1 and 9 months: 1-3 months for a lift & shift, 4-9 months for a refactor. A 2- to 4-week prior audit phase is essential to price it accurately.
Is the cloud really cheaper than on-premise?
Over time, yes: up to -30 % in operating costs thanks to no hardware, automatic backups and elasticity. Beware of right-sizing, though, to avoid overspend.
Do I have to rewrite everything?
Rarely. A gradual approach (rehost then module-by-module refactor) cuts risk and spreads the investment. A full rewrite is justified mainly when the code is unmaintainable or the stack abandoned.
How to guarantee continuity during migration?
With an iso-production test environment, a cutover scheduled outside business hours and a rollback plan. In 2026, a well-orchestrated migration limits downtime to a few hours.
Let's scope your project. Send us a description of your legacy app (stack, volume, criticality): we audit and recommend the best-value migration strategy. 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.
