The timeline to do an Access to SQL Conversion project manually is governed exclusively by its level of software complexity – the amount of data contained in the Access tables per se is of little relevance. A very quick way to estimate software complexity is to count the number of tables, queries, forms, reports and modules (including class modules).
If the total of these is in the low hundreds or less, then it is most likely that the database is of low complexity, requiring only days to weeks to convert manually. A total of less than 1,000 equates to medium complexity, which will require months to convert manually. However, a total of over 1,000 tables, queries, forms, reports and modules generally indicates typically high complexity, and these can take over a year each to convert manually.
The reason why complexity typically increases proportional to the object count of a database is because these objects need to communicate with one another by way of SQL Expressions. The more objects there are, the more permutations possible in how these SQL Expressions can be written.
2SQL goes much further than the object count of a database to measure its complexity. On completion of a scan by the 2SQL Detective, a conversion estimate screen will display which shows a detailed analysis across the 30+ Conversion Categories, the number of issues for each category, the complexity rating, and the number of minutes to manually convert each issue. Samples of these are on our Empirical Case Studies page.