Knowledge Base - Technical Articles

Technical Article   HowTo:  Change the data type for an existing field

Article ID: 34315
Software:  ArcGIS - ArcEditor 9.0, 9.1, 9.2, 9.3, 9.3.1, 10 ArcGIS - ArcInfo 9.0, 9.1, 9.2, 9.3, 9.3.1 ArcGIS - ArcView 9.0, 9.1, 9.2, 9.3, 9.3.1
Platforms:  Windows XP, 2003Server, Vista


Instructions provided describe the steps to transfer data from a field of one data type to a field with any data type desired.


Sometimes attributes are stored in fields of a specific data type with limited capabilities, for example, math functions cannot be performed on text fields, because integers do not store decimals. While it is not possible to change the data type of a field, there is a way to get the same results.

  1. In ArcMap, right-click on the name of the feature class whose table is to be modified and select Open Attribute Table.
  2. In the attribute table, click the Options button and select Add Field. Enter a name for the new field. Set the data type and its properties. Click OK.
  3. Right-click on the new field and select Field Calculator. Then double-click on the name of the field whose data type is to be changed. Click OK.
     When converting from a text field to a field with a numeric data type, remember that the text must have numbers and no other characters, except decimal points.

  4. The new field now contains the data from the previous field, but it is stored as a different data type. Delete the old field, if necessary.

Related Information

Created: 1/17/2008
Last Modified: 5/3/2011

Article Rating: (1)
If you would like to post a comment, please login


By SabrinaHeeremaAgostino - 10/25/2012 4:45 AM

The article needs to be updated.

How to change the data type of an existing field In this case we have an Excel document with fields of data type ‘number’. To use the excel in ArcGIS (ArcView 10.1) you will need to import it. But first, 1. Create a file geodatabase 2. Import the excel into the file geodatabase. The result will be a table. 3. Right-click this resulting table and select ‘display XY data’, which will allow the data to be displayed in ArcMap. The problem here is that ArcGIS automatically converts numeric fields from Excel to double data type. In this case, a double data type is not suitable for the use of the data. It is possible to change the data type back to its’ number form without using the ‘add a new field and use field calculator’ technique, which I want to avoid since I have to manually change the type for many fields. To do so, you can do the following: 4. Open the tool ‘Feature to Feature’ from the Conversion tools, to Geodatabase toolset. Specify the input and ouput. Notice that under Field Map, the data type of all fields is specified. In this case, the data type is still double, which we want to change. 5. Under Field Map, open the properties of the field you want to change. 6. Change the data type. 7. Notice that the type has also changed in the Field Map list. Yay! 8. Run the tool. 9. When it has finished, open up the layer properties of the result layer to observe that the data type has indeed been changed. Caution: You may lose some data if it fails to convert data type for some values. Take this risk into consideration.


By ryanptucker - 09/06/2012 10:48 AM

The article is incorrect or the solution didn’t work.

There is actually an easier way to change the field type. Export the Table to another table. Before you export, just change the field type under properties for the fields listed in the window. Just did this for a table that had text fields that should have been Double fields.