Is it possible to duplicate a dashboard in grafana?

Yes you can duplicate a dashboard. Just save it with a different name. Click on the save icon change the name and it will be saved with a new name (the old one will still exist)

New versions got a "Save As..." button in the dashboard menu:

I ended up doing this by exporting the existing dashboard, re-importing it, making my changes, and then saving it with a different title.

Yes, We can duplicate the dashboard,

Setting--> Save As.

Settings view: