Outgrowing Access? Move up to SQL Server.

An Access-to-SQL migration splits cleanly into what transfers easily and what needs actual judgment. Tables, data, and relationships move well, with a few precise decisions along the way: AutoNumbers become identity columns, Access dates map to appropriate SQL types, and Yes/No fields need explicit defaults, or you meet the classic bug where a form silently stops accepting edits because a bit column allows nulls. I also add rowversion columns to the migrated tables, an unglamorous detail that makes editing through linked tables far more reliable.

Queries are where the judgment goes. Simple selects re-link and just work. But Access-specific functions (Nz, domain lookups, any VBA function used inside a query) don't exist on the server, and a query that was slow in Access can stay slow if it's merely re-pointed rather than rethought. The heavy lifters get rewritten as views or stored procedures so the server does the aggregation and only results cross the network. That rewrite, not the data transfer, is where the performance you're migrating for actually comes from.

Your forms and reports mostly survive as-is, which is the whole point of keeping Access as the front end. The exceptions are patterns that were only ever viable against local tables, like forms bound directly to a large table that now drag too much across the wire; those get re-based on filtered queries that fetch only what the screen needs. VBA that edits data through DAO needs small, specific adjustments for linked SQL tables, the dbSeeChanges requirement being the one everybody hits first.

On cost: the server itself is often free. SQL Server Express handles databases up to 10 GB at no license cost, which comfortably covers most systems graduating from Access, and it can run on a machine you already own or a modest cloud instance. Azure SQL suits teams that want the database reachable from multiple sites without hosting anything themselves. So the real project cost is the migration work, not the software, and the Express-to-full upgrade path exists if you ever genuinely outgrow the free tier.

I migrate to a test SQL database and run both systems side by side against real work before anything cuts over. The rule of thumb I give clients: if you're approaching the 2 GB file limit, pushing past roughly ten concurrent users, or losing sleep over corruption, you've outgrown the Access back-end, and this migration is the fix built for exactly that situation.