A transparent pricing guide for legacy system modernization based on 500+ projects we have delivered. Real numbers, not marketing ranges.
Quick answer: Legacy system modernization costs $40,000–$500,000+ depending on system age, complexity, and modernization strategy. A UI modernization costs $40K–$100K. A phased re-platforming runs $100K–$250K. Full system re-architecture costs $250K–$500K+. Want a tailored estimate? Talk to us →
$40K–$100K
New frontend on existing backend, API wrapper around legacy, improved UX without core changes.
8–16 weeks
$100K–$250K
Migrate to modern stack, containerization, cloud deployment, database migration, and new integrations.
16–32 weeks
$250K–$400K
Decompose monolith into microservices, event-driven architecture, modern data layer, and new frontend.
8–14 months
$400K–$500K+
Complete ground-up rebuild with modern architecture, zero-downtime migration, and feature parity.
12–18+ months
A 10K-line monolith is manageable. A 500K-line system with decades of business logic encoded in code requires extensive analysis and careful migration — doubling or tripling costs.
Well-documented systems are cheaper to modernize. Undocumented systems require reverse engineering, which adds $15K–$50K for business logic discovery.
Clean relational data is straightforward. Legacy databases with denormalized schemas, stored procedures, and data quality issues add $15K–$40K for migration and cleansing.
Systems that can have a maintenance window are cheaper to migrate. Zero-downtime requirements with the strangler fig pattern add $20K–$50K for parallel running.
Each legacy integration (files, SOAP, direct DB connections) that needs modernization adds $5K–$15K for API wrapping or replacement.
Maintaining SOX, HIPAA, or industry compliance during modernization adds $10K–$30K for audit trail continuity and revalidation.
System audit, business logic documentation, risk assessment, migration strategy
Target architecture, technology selection, data model, integration design
Phased migration, API wrappers, service extraction, data migration
Regression testing, data validation, performance benchmarking, UAT
Final cutover, legacy decommission, monitoring, team training
Practical steps we use with clients to control scope and spend.
Plan for discovery, a realistic MVP, and a 15–20% contingency before you lock a number for legacy system modernization. Scope changes and integrations are where estimates drift — we help you sequence work so you fund value in the right order.
Share your goals and timeline — we will map scope, options, and a clear investment range.
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