Determining Your Isolation Level

Bob Pusateri explains different transaction isolation levels and where you can figure out your current settings:

Isolation level settings for the entire database exist only as a default. All connections created will inherit the database’s isolation level. Furthermore, a database only has two possible isolation levels:
– read committed
– read committed snapshot (also known as “RCSI”)

There are four additional isolation levels (read uncommitted, repeatable read, serializable, snapshot) which can only be selected at the connection or statement level. In SQL Server and Azure SQL Database Managed Instance, the default database isolation level is read committed. In Azure SQL Database, the default is read committed snapshot.

Read the whole thing.