You can copy a widget by following these simple steps:

  1. Open the dashboard in change mode
  2. Click on the copy button (pic 1)
  3. Select the dashboard you want to copy the widget to, from the the dropdown list (pic2)

Pic 1

https://s3-us-west-2.amazonaws.com/secure.notion-static.com/cc343271-5e8d-4027-9a43-5ff0401dec61/image2018-1-16_14-39-43.png

Pic 2

https://s3-us-west-2.amazonaws.com/secure.notion-static.com/72826acc-c510-45f9-b1be-f21e6e53d6ac/image2018-1-16_14-43-42.png