# Tag mapping
Tags are key-value pairs used to organize and provide additional context to the cost data.
In Cloud Cost Management, the Project and Environment fields are derived from the tags’ values. On the Tag Mapping page, you can customize how the tags are parsed by entering the keys you use for denoting a project or an environment.
For example, with the configuration of the following screenshot, the values of tags with key user:project
or project
will be used to populate the Project field, and the values of tags with key env
will populate the Environment field.
If selecting several tag keys is not enough for your use case, you can specify a regular expression in the Advanced tab instead. For example, using the configuration of the following screenshot, the key env
will again be used for the Environment field, but the same will happen with keys Env
, environment
, etc.