Migrating from BigCommerce to Magento — realistic timeline and cost?

Weeks 1&ndash;2: Discovery + architecture + Magento + Hyv&auml; install + dev environment.
Weeks 3&ndash;5: Catalog + customers + orders migration via Cart2Cart / LitExtension or a custom export-import. URL redirect map (BC URLs differ from Magento&rsquo;s &mdash; SEO-critical).
Weeks 4&ndash;7: Theme rebuild on Hyv&auml; (BC Stencil themes don&rsquo;t port; Hyv&auml; is the modern replacement).
Weeks 5&ndash;8: Payment / shipping / tax reconnection, B2B feature setup, app replacements (each BC app needs a Magento equivalent).
Weeks 8&ndash;10: ERP / WMS / ESP integrations.
Weeks 10&ndash;12: UAT, performance tuning, cutover with 14-day rollback window.

Question

Accepted Answer

For a typical mid-market store (1k–10k SKUs, B2B + B2C, 2 years of order history): $15k–$30k and 8–12 weeks end-to-end.

Phases:

Weeks 1–2: Discovery + architecture + Magento + Hyvä install + dev environment.
Weeks 3–5: Catalog + customers + orders migration via Cart2Cart / LitExtension or a custom export-import. URL redirect map (BC URLs differ from Magento’s — SEO-critical).
Weeks 4–7: Theme rebuild on Hyvä (BC Stencil themes don’t port; Hyvä is the modern replacement).
Weeks 5–8: Payment / shipping / tax reconnection, B2B feature setup, app replacements (each BC app needs a Magento equivalent).
Weeks 8–10: ERP / WMS / ESP integrations.
Weeks 10–12: UAT, performance tuning, cutover with 14-day rollback window.

Faster & cheaper paths exist for very simple stores ($5k–$10k, 6 weeks). Bigger / heavier-customization stores creep to $50k+ and 16 weeks — budget accordingly.