How Much Does eCommerce Replatforming Cost in 2026?
your project?
A straightforward store migration can run $25,000. A complex B2B replatform with deep integrations can run past $500,000. Both are "eCommerce replatforming," and the gap between them comes down to a handful of factors most budgets underestimate before the project starts.
eCommerce replatforming cost is one of the widest ranges in ecommerce spending, and the range itself is the first useful data point: if a vendor quotes you a number without asking about your integrations, your data volume, and your custom logic, that number is a guess, not an estimate.
The real cost range for 2026
Industry cost benchmarks put replatforming into roughly four tiers by complexity:
For most mid-market businesses, a realistic all-in budget lands around $150,000 to $300,000, over a 5 to 10 month timeline. That range assumes a reasonably clean starting point. Legacy data, undocumented custom code, or a large B2B catalog push it toward the higher end fast.
Where the money actually goes
The most common budgeting mistake is treating the platform license as the main cost. It rarely is. Platform licensing typically accounts for only 20 to 40 percent of the total project cost. The remaining 60 to 80 percent goes to implementation: integration work, data migration, custom development, QA, and project management.
A cheap platform license does not produce a cheap project if the implementation work underneath it is the same regardless of which platform you chose. Budgeting around the license price alone is how projects blow past their number in month three.
The single biggest risk to your budget
Data migration is where replatforming budgets most often break. Industry reporting puts the failure or budget-overrun rate for the data migration portion of these projects at roughly 83 percent, the highest risk component of the entire process. Product catalogs, customer records, order history, and custom attributes rarely map cleanly from one platform's data model to another's, and that mismatch is usually discovered mid-project instead of budgeted for at the start.
If your replatforming budget has a generous line for the new platform and a thin one for data migration, the number is backwards. Migration is where the real risk, and the real cost, tends to live.
What drives the number up or down
- integration count and complexity. Each ERP, PIM, tax, fulfillment, or marketing connection is real engineering work, not a checkbox;
- data volume and cleanliness. A large, messy, undocumented catalog costs far more to migrate than a small, clean one;
- custom business logic. Pricing rules, B2B workflows, and checkout customizations that do not exist on the new platform need to be rebuilt, not copied;
- headless versus templated. A composable, headless build costs more up front than a templated theme, and the number reflects that added flexibility;
- risk tolerance for the cutover. A rushed, single-event cutover is cheaper to plan and more expensive when something goes wrong; a phased, parallel-run migration costs more up front and protects revenue;
- who does the work. Agency rates, freelancer rates, and in-house team costs vary enormously, and cheaper hourly rates do not reliably produce cheaper total projects if the team is inexperienced with your specific complexity.
How to avoid budget overruns
- run a real audit before requesting quotes. A vendor cannot price integrations, data volume, or custom logic they do not know exist;
- get a data migration plan with its own line item, not a vague inclusion inside "implementation";
- phase the migration where possible, validating each stage instead of committing the full budget to one cutover event;
- push for fixed-scope pricing on defined phases, with clear change-order terms for anything discovered later;
- budget a real contingency, typically 15 to 20 percent, for the undocumented complexity that audits do not always catch.
Conclusions
eCommerce replatforming cost in 2026 spans from $15,000 for a simple migration to well over $500,000 for a complex enterprise build, and the platform license itself explains very little of that range. Integration complexity, data volume, custom logic, and migration risk are what actually set the number, with data migration carrying the highest risk of blowing the budget. Audit before you quote, plan migration as its own workstream, and treat any number that ignores these factors as a placeholder, not an estimate.