Is there way to create a calculated column to show the age of an issue? Basically, I would want to do a formula for a custom field to be [current date] - [created date].
Jira Product Discovery is keeping its ideas as Jira issues under the hood so any reporting that works for issues should also work for them.
The closest you can get with out-of-the-box Jira is the Average Age Chart, which is available as a dashboard gadget. It is very limited in terms of details and flexibility.
For more details and flexibility, I suggest you use a marketplace app.
If you are OK with using a marketplace app, our team at OBSS built Time in Status exactly for this. It is available for Jira Server, Cloud, and Data Center.
Time in Status mainly allows you to see how much time each issue spent on each status or each assignee.
You can combine the time for multiple statuses to get metrics like Issue Age, Cycle Time, Lead Time, Resolution Time etc.
For all numeric report types, you can calculate averages and sums of those durations grouped by the issue fields you select. For example total in-progress time per customer or average resolution time per sprint, week, month, issuetype, request type, etc. The ability to group by parts of dates (year, month, week, day, hour) or sprints is particularly useful here since it allows you to compare different time periods or see the trend.
The app calculates its reports using already existing Jira issue histories so when you install the app, you don't need to add anything to your issue workflows and you can get reports on your past issues as well. It supports both Company-Managed and Team-Managed projects for Jira Cloud.
Time in Status reports can be accessed through its own reporting page, dashboard gadgets, and issue view screen tabs. All these options can provide both calculated data tables and charts.