# Tag AWS Certificate Manager resources
A *tag* is a label that you can assign to an ACM certificate. Each tag consists of a *key* and a *value*. You can use the AWS Certificate Manager console, AWS Command Line Interface (AWS CLI), or ACM API to add, view, or remove tags for ACM certificates. You can choose which tags to display in the ACM console.
You can create custom tags that suit your needs. For example, you could tag multiple ACM certificates with an `Environment = Prod` or `Environment = Beta` tag to identify which environment each ACM certificate is intended for. The following list includes a few additional examples of other custom tags:
+ `Admin = Alice`
+ `Purpose = Website`
+ `Protocol = TLS`
+ `Registrar = Route53`
Other AWS resources also support tagging. You can, therefore, assign the same tag to different resources to indicate whether those resources are related. For example, you can assign a tag such as `Website = example.com` to the ACM certificate, the load balancer, and other resources used for your example.com website.
**Topics**
+ [Tag restrictions](tags-restrictions.md)
+ [Managing tags](tags-manage.md)
# Tag restrictions
The following basic restrictions apply to ACM certificate tags:
+ The maximum number of tags per ACM certificate is 50.
+ The maximum length of a tag key is 127 characters.
+ The maximum length of a tag value is 255 characters.
+ Tag keys and values are case sensitive.
+ The `aws:` prefix is reserved for AWS use; you cannot add, edit, or delete tags whose key begins with `aws:`. Tags that begin with `aws:` do not count against your tags-per-resource quota.
+ If you plan to use your tagging schema across multiple services and resources, remember that other services may have other restrictions for allowed characters. Refer to the documentation for that service.
+ ACM certificate tags are not available for use in the AWS Management Console's [Resource Groups and Tag Editor](https://aws.amazon.com/blogs/aws/resource-groups-and-tagging/).
For general information about AWS tagging conventions, see [Tagging AWS Resources](https://docs.aws.amazon.com/general/latest/gr/aws_tagging.html).
# Managing tags
You can add, edit, and delete tags by using the AWS Management Console, the AWS Command Line Interface, or the AWS Certificate Manager API.
## Managing tags (console)
You can use the AWS Management Console to add, delete, or edit tags. You can also display tags in columns.
### Adding a tag
Use the following procedure to add tags by using the ACM console.
**To add a tag to a certificate (console)**
1. Sign into the AWS Management Console and open the AWS Certificate Manager console at [https://console.aws.amazon.com/acm/home](https://console.aws.amazon.com/acm/home).
1. Choose the arrow next to the certificate that you want to tag.
1. In the details pane, scroll down to **Tags**.
1. Choose **Edit** and **Add Tag**.
1. Type a key and a value for the tag.
1. Choose **Save**.
### Deleting a tag
Use the following procedure to delete tags by using the ACM console.
**To delete a tag (console)**
1. Sign into the AWS Management Console and open the AWS Certificate Manager console at [https://console.aws.amazon.com/acm/home](https://console.aws.amazon.com/acm/home).
1. Choose the arrow next to the certificate with a tag that you want to delete.
1. In the details pane, scroll down to **Tags**.
1. Choose **Edit**.
1. Choose the **X** next to the tag you want to delete.
1. Choose **Save**.
### Editing a tag
Use the following procedure to edit tags by using the ACM console.
**To edit a tag (console)**
1. Sign into the AWS Management Console and open the AWS Certificate Manager console at [https://console.aws.amazon.com/acm/home](https://console.aws.amazon.com/acm/home).
1. Choose the arrow next to certificate you want to edit.
1. In the details pane, scroll down to **Tags**.
1. Choose **Edit**.
1. Modify the key or value of the tag you want to change.
1. Choose **Save**.
### Showing tags in columns
Use the following procedure to show tags in columns in the ACM console.
**To display tags in columns (console)**
1. Sign into the AWS Management Console and open the AWS Certificate Manager console at [https://console.aws.amazon.com/acm/home](https://console.aws.amazon.com/acm/home).
1. Choose the tags that you want to display as columns by choosing the gear icon ![\[Gear or settings icon, represented by a simple cog wheel symbol.\]](http://docs.aws.amazon.com/acm/latest/userguide/images/acm-gear-icon-console.png) in the upper right corner of the console.
1. Select the check box beside the tag that you want to display in a column.
## Managing tags (CLI)
Refer to the following topics to learn how to add, list, and delete tags by using the AWS CLI.
+ [add-tags-to-certificate](https://docs.aws.amazon.com/cli/latest/reference/acm/add-tags-to-certificate.html)
+ [list-tags-for-certificate](https://docs.aws.amazon.com/cli/latest/reference/acm/list-tags-for-certificate.html)
+ [remove-tags-from-certificate](https://docs.aws.amazon.com/cli/latest/reference/acm/remove-tags-from-certificate.html)
## Managing tags (ACM API)
Refer to the following topics to learn how to add, list, and delete tags by using the API.
+ [AddTagsToCertificate](https://docs.aws.amazon.com/acm/latest/APIReference/API_AddTagsToCertificate.html)
+ [ListTagsForCertificate](https://docs.aws.amazon.com/acm/latest/APIReference/API_ListTagsForCertificate.html)
+ [RemoveTagsFromCertificate](https://docs.aws.amazon.com/acm/latest/APIReference/API_RemoveTagsFromCertificate.html)