What actually shapes a modernization estimate?
A count of screens can describe the interface. It will not tell you how much history must move, which integrations must keep working or how the business will switch to the new version.
Ask for work you can examine
An estimate should distinguish investigation, design, implementation, integrations, migration, testing and rollout. Under each area, ask what is known, what is assumed and what still needs access or a technical check.
A range should explain its uncertainty. If an undocumented API is responsible for a large part of that range, ask which investigation would narrow it. A fixed price needs a defined scope and a clear agreement about changes.
Worked example: replacing an internal operations app
Suppose a business wants to replace a browser-based application used to manage customers, orders and approvals. To see how an estimate adds up, use the following scope:
- One responsive web application, three user roles and seven agreed workflows.
- Two external systems with documented APIs, test access and named technical contacts.
- Up to 80,000 customer and order records in an accessible database, with a representative sample checked during investigation. The client owns data cleanup.
- One migration rehearsal, an agreed maintenance window for cutover, rollback checks and a handover to the client's product owner.
The example excludes native mobile apps, a new accounting system, a 24/7 support commitment and formal third-party security or accessibility audits. An uninterrupted cutover would need its own transition design and estimate.
For the calculation below, assume €60 per delivery hour across the roles involved. This is a worked planning example, not a customer budget or a quote; replace the rate and effort with those in the proposal you are evaluating.
| Work | Hours | At €60/hour |
|---|---|---|
| Investigation and technical checks | 40–60 | €2,400–€3,600 |
| Workflow and interface design | 40–60 | €2,400–€3,600 |
| Core application and business rules | 200–260 | €12,000–€15,600 |
| Two external integrations | 60–80 | €3,600–€4,800 |
| Data migration and reconciliation | 60–80 | €3,600–€4,800 |
| Testing and fixes | 120–160 | €7,200–€9,600 |
| Release preparation, cutover and handover | 80–100 | €4,800–€6,000 |
| Total delivery effort | 600–800 | €36,000–€48,000 |
A 15% planning reserve adds €5,400–€7,200, giving a planning envelope of €41,400–€55,200 before VAT. Here the effort range reflects remaining uncertainty within the defined scope; the reserve is a separate allowance for agreed risks. It is not extra scope to spend automatically. A proposal should state who can authorize its use.
Hosting, paid services and ongoing maintenance sit outside that delivery figure and need separate estimates. The hours are total team effort; calendar duration depends on available capacity, access to the old system and the client's review schedule.
What would change this estimate?
If the data sample reveals conflicting customer IDs, reconciliation needs more work. If an API does not support the required update, the integration design changes. If both versions must run together during the transition, allow for synchronization and another set of checks. Record each finding against the affected work item and revise the range before committing to delivery.
For an initial discussion of your own scope, use the project estimate wizard. To test whether the planned improvements justify the investment, use the workflow productivity calculator with your own handling times, review effort and volumes.
Include the transition
Discuss data cleanup, migration rehearsals, reconciliation, training, temporary operation and rollback. Give those activities an owner. Moving a database and moving a business to the new system are related work, but they are not the same task.
MERP/PREP combined a web, mobile and backend rewrite with DevOps and migration. The delivery team reports a cutover without service interruption and 90% lower AWS costs afterwards. Those project outcomes illustrate the scope; they are not a price or savings forecast for another platform.
Clarify the cost after release
Separate hosting and third-party services from maintenance, support coverage and continuing product development. Ask what the engagement includes and what needs a separate arrangement.
We do not publish a universal modernization price because the existing software and transition requirements differ. Our pricing approach explains how we establish the scope, and our modernization work covers the change around the code.
