The Excel To Table tool does not create proper field types.
Last Published: February 14, 2017ArcGIS for Desktop
Bug ID Number
October 16, 2015
November 24, 2020
ArcGIS for Desktop
This issue was not reproducible when tested by the development team. Issues may be given this status when they cannot be reproduced or are no longer relevant in a development version of the software, but a specific fix was not installed to address the issue. The issue's Additional Information section may contain further explanation.
The document was fixed a few releases ago. The output field type is controlled by all field values, not just the first 8.
Convert the field to a new field type in ArcMap after importing by using the Calculate Field tool.This knowledgebase article states it is only for older versions of ArcMap but works in newer versions as well:Article # 34315: Change the data type for an existing field<a href="http://support.esri.com/em/knowledgebase/techarticles/detail/34315" target="_blank">http://support.esri.com/em/knowledgebase/techarticles/detail/34315</a>