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EF Core - The conversion of a datetime2 data type to a datetime data type resulted in an out-of-range value

Athough EF Core is a developer friendly Object-Relational Mapper (ORM), working with it isn't without its challenges. One error that we encountered during a pair programming session was:

The conversion of a datetime2 data type to a datetime data type resulted in an out-of-range value

In this blog post, we will delve into the causes of this error and explore ways to resolve it.

"Constructing a database in the 18th century" - Generated by AI

Understanding the error

This error typically occurs when there is an attempt to convert a datetime2 value in SQL Server to a datetime value, and the value falls outside the valid range for the datetime data type.

  • datetime: This data type in SQL Server has a range from January 1, 1753, to December 31, 9999, with an accuracy of 3.33 milliseconds.
  • datetime2: This newer data type, introduced in SQL Server 2008, has a much broader range from January 1, 0001, to December 31, 9999, with an accuracy of 100 nanoseconds.

When EF Core tries to map a .NET DateTime to SQL Server’s datetime, any value outside the range of January 1, 1753, to December 31, 9999, will cause this conversion error.

Remark: Wondering why January 1, 1753? Read about the Gregorian calendar here.

Let’s fix it!

One reason that this error can occur is when your DateTime is set to DateTime.MinValue which is January 1, 0001. This value is valid for datetime2 but not for datetime, leading to the out-of-range error.

Initialize your DateTime properties with a value that is within the range of the SQL Server datetime type.(e.g. 1/1/1753).

Another solution is to use the datetime2 type explicitly in your EF Core model configurations to avoid range issues:

There is a third solution in case this error happens because you try to map a nullable database column to a non-nullable property. In that case you could change the property to make it nullable:

Remark: Instead of using a DateTime type consider using the DateOnly type when you only care about the Date part.

More information

What's New in EF Core 8 | Microsoft Learn

Entity Framework Core–DateOnly and TimeOnly (bartwullems.blogspot.com)

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